Greek roots

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Etymology, the anatomy of words, is a dynamic method for expanding academic vocabulary. Editors of the Oxford English Dictionary hypothesize that biology has added about 60,000 words to our glossary, more than any other field of knowledge. While some use mnemonic devices to memorize key terms, etymology provides tools for the analysis of words not previously encountered.

Greek thought provided a basis for such modern neologisms as chromosome, electrocardiogram, and atomic theory. The names for the sciences themselves derive from Greek: geometry, chemistry, physics, anatomy, psychology, and economics are all examples. (In the scheme used in these paragraphs, words typed in italics share a Greek genesis). We call the study of insects entomology (instead of “insectology”) because the word "insect" is Latin while the suffix -logy is Greek (entomos and insect both refer to bodies that are "cut in segments"). Greek and Latin share many homologous word pairs — synonyms with the same underlying logic such as hypoglossal and sublingual. In part, this reflects a dichotomy between medicine and surgery (for much of their history, the two professions had little dialogue). While physicians employed Latin phrases, surgeons opted for the language of Aristotle. Though spellings have morphed (from an alphabet with two O's, two E's and no H), Greek ideas about mathematics, politics, and poetry still influence our thought.

The following word lists include many examples from science and the humanities descended from Ancient Greek (often via Latin). Parallel lists of Latin and Semitic roots are also available. Return to Science for additional interdisciplinary resources.


A α alpha

The Greek letter alpha is used to identify the first in a series and is the beginning of our word alphabet. For example, an alpha wolf is the leader of a pack. In organic chemistry, the alpha carbon is the first carbon in a hydrocarbon chain while an alpha helix is the protein structure with the most hydrogen bonding. In physics, alpha particles are the form of radiation most easily blocked by a barrier while alpha centauri is the brightest star in the constellation Centaur (and also the closest to our solar system). Greek words beginning with alpha followed by epsilon were once spelled with the English diphthong æ as in aether and aesthetics, but modern spellings have dropped the a for simplicity (ether and esthetics).

Root Stem Meaning Examples
a-, an- without, not asymmetry, atheism, atrophy, apnea, ataxia, aphasia, avascular, anemia, anaerobic, anesthesia, analgesic, anomaly, aneuploidy
ἀγρός agro- field, farmland agriculture, agronomy, agribusiness, acre, onager
ἄγωγή agog- lead, convey, flow agony, antagonize, demagogue, glucagon, protagonist, pedagogy, synagogue, secretagogue, hypnagogic, mystagogue
ἄδεν adeno- full, abundant, gland adenoid, adenoma, adenohypophysis, adenovirus, sialadenitis, hidradenitis, lymphadenectomy
ἀήρ aero- air, atmosphere aerobic, aerate, aerial, aerie, aerofoil, aerosol, aeroplane, aerophyte, aura, malaria
ἆθλητήρ athl- athlete, champion athlete, triathlon, decathlon, mathlete
αἴθρη æther- clear air, sky ether, ethereal, ethernet, ethane, ethyl, ethanoic, ethanol, ester, esterification, polyester, acetylcholinesterase
αἷμα hema- blood hemoglobin, hemophilia, hematology, hematocrit, polycythemia, anemia, leukemia, azotemia
αἲσθησις æsthe- to feel, perceive esthetic, anesthesia, anesthiology, kinesthetic, paresthesia, synesthesia
αἲτιος ætio- cause etiology
ἂκρος acro- apex, extremity acromion, acromegaly, acrobat, acronym, acrostic, acrophobia, acropolis, acrosome
ἀκτίς actino- ray actin, actinic, actiniform, actinium, actinide, actinomyces, actinopterygian, octactinal
ἀλγέω algo- pain algophobia, neuralgia, myalgia, arthralgia, analgesic, causalgia
ἀλλήλους allelo- one another, each other allele, allelomorph, allelopathy, parallel, parallax
ἂλλος allo- another, foreign allergy, allegory, allograft, allotrope, allopathic, allometric, alien, alias, alibi
ἃλς halo- sea, salt halogen, halite, halophyte, halophile, halcyon
ἁμαρτάς hamarto- fatal flaw, sin hamartia, hamartiology, hamartoma
ἀμφί amphi- two-sided, both amphiarthrosis, amphibian, amphibole, amphipathic, amphitheater, amphoteric, amphotericin
ἀνά ana- up, through, again analysis, anaphase, anagram, anode, anabolic, anachronism, analogy, anatomy, anastomosis, anaphylaxis, anathema
ἀνδρόμεος andro- man, husband androgen, android, androgynous, androstenedione, protandry, polyandry, philanderer
ἂνθραξ anthrac- coal anthrax, anthracite, anthrocene, anthracosis
ἂνθρωπος anthrop- man, human being anthropic, anthropology, anthropomorphism, anthropoid, philanthropy, misanthrope, lycanthropy
ἄνιμα anima- breath, life anima, animal, animated, animism, equanimity, manganimous, pusillanimous, unanimous, anemone
ἀντί anti- against, opposing antacid, anti, antigen, antibody, antibiotic, antidote, antithesis, antisense, antipodes, antiphonal, anthem
ἂξων axo- axis, central axon, axoneme, axonometric, axophyte, axoplasm, axiom, chronaxie
ἁπλόος haplo- simple, single haploid, haplotype, haplont, haplopia, haplodont
ἀπό apo- from, away, off apocrine, apoprotein, apoptosis, apology, apocryphal, apothem, aponeurosis, apoplexy, apostle, apotheosis
ἃπτω apse- juncture, fasten apse, synapse, synaptic, presynaptic, postsynaptic, synapsid, therapsid, hapten
ἀράχνη arachno- spider, web arachnid, arachnoid, arachnophobia
ἀργός argo- white, silver, swift argon, argonaut, argyria, argyrum, hydrargyrum, argillite, arginine
ἂρθρον arthro- joint, speech arthritis, arthralgia, arthropathy, arthropod, condylarth, diarthrosis, dysarthria, synarthrosis, xenarthra
ἁρμονίᾶ harmon- harmony, agreement harmony, harmonic, harmonious, harmonica, enharmonic
ἀρτηρίᾶ arteri- artery, windpipe aorta, artery, arteriole, arteritis, arteriosclerosis
ἀρχή arche- first, principal, chief archaic, anarchy, monarchy, archangel, archeology, archetype, arch-enemy, archosaur, archipelago, architecture, menarche
ἂστρον astro- star aster, asterism, asteroid, asterisk, astrocytoma, astronomy, astronaut, astrolabe, astrology, disaster
αὒξη aug-, aux- aid, increase, growth augment, auxiliary, auxin, auxesis, auction, author
αὐτός auto- self autotroph, autopsy, autosome, autonomic, autograft, automobile, autocratic, automatic, automaton, autism, autobiography

B β beta

The Greek letter beta is used to identify the second in a series. For example, the beta carbon is the second carbon of a hydrocarbon chain and a beta sheet is the second most important protein structure. The beta particle, also called an electron, is the second type of radiation to be blocked. In biology, beta cells secrete inulin while beta receptors are activated by adrenalin. In product development, beta testers evaluate a product after its initial testing in the lab.

Root Stem Meaning Examples
βακτερίᾶ bacteri- rod, staff bacterium, bacteria, bacteremia, bacteriuria, antibacterial, bacteriophage, bactericidal, bacteriostatic, helicobacter
βαρβαρος barba- bearded, foreign barb, barbed, barbicel, barbule, barber, barbarian, barbarous, barbary, beard
βαρύς baro- pressure, heavy, weight barite, baryon, barium, baritone, barometer, baroreceptor, barotrauma, bariatric, barycentric, isobar, dysbarism
βάσις baso- foundation, low, step base, basis, basal, basophilic, baseball, bass, bas relief, acrobat, diabase, diabetes, anabaena, katabatic, stylobate
βίος bio- life biota, biology, biotin, biography, biopsy, biome, biosphere, abiogenesis, symbiosis, amphibious, antibiotic, microbe
βλαστός blast- bud, sprout blastula, blastoderm, blastocyst, epiblast, hypoblast, ameloblastoma, osteoblast, megaloblastic
βλεφαρίς blepharo- eyelid blepharitis, blepharoplasty, blepharisma, blepharospasm, symblepharon, calliblephary, pachyblepharosis
βολή bola- throw, stroke, ball ball, ballistics, balloon, bolus, bullet, bulletin, amphibole, embolus, metabolism, anabolic, parabola, hyperbola, hyperbole
βουβών bubo- groin, lymph node bubonic, bubonalgia, bubo, bubonocele
βοῦς bou- ox, cattle boustrophodon, butter, butyric, butyraceous, butyl, butane, bovine, Bosphorus
βράγχος bronch- gills, throat, sore throat branchial, branchiopod, elasmobranch, opisthobranch, nudibranch, bronchus, bronchial, bronchitis, bronchoscopy, rhonchus
βραδύς brady- slow, lazy bradycardia, bradylexia, bradykinin, bradypod
βραχύς brachy- short brachistochrone, brachydactyly, brachyodont, brachysm, amphibrach, tribrach
βρόμος bromo- food, belch, rumbling bromine, bromide, bromocryptine, bromthymol, theobromine, borborygmi
βροντή broto- thunder brontosaurus, brontotherium, brontology, brontophobia
βρύον bryo- moss, growth, swelling bryology, bryophyte, bryozoan, embryo, embryogenesis, embryology, embryonic

Γ γ gamma

The letter gamma is third in the Greek alphabet, and so identifies the third in a series (there is no letter C in ancient Greek). The gamma carbon is the third in a chain, as in gamma-aminobutyric acid (or GABA) while gamma rays are the third major form of radioactivity and are capable of passing through the human body. Greek words with a double gamma, γγ, have an ng sound as in thing or ganglion. When gamma is followed by xi, γξ, the word is pronounced nx as in phalanx or larynx. These words become modified to ng in the plural (phalanges) or adjectival forms (laryngeal).

Root Stem Meaning Examples
γάγγλιον ganglio- knot, swelling ganglion, ganglia, ganglioglioma, paraganglioma, preganglionic
γαῖα, γη geo- earth, land geometry, geography, geology, geocentric, geochemist, geophagy, geode, geodesics, geotaxis
γάλα galacto- milk galactose, galactorrhea, galaxy, intergalactic
γαμέω gamo- marriage, union gamete, gametogenesis, bigamy, monogamy, polygamous, autogamy
γάστρᾶ gastro- stomach, belly gastric, gastrin, gastrocnemius, gastropod, gastronomic, gastroparesis, digastric
γένειον genio- jawbone, chin genial, genioglossus, geniohyoid, genioplasty
γένος gen- birth, descent antigen, pepsinogen, teratogen, genetics, gene
γῆρας gero- old age, elderly gerontology, gerontocracy, geriatrics, ageratum, geritol, progeria
γίγᾶς giga- giant, very large, billion gigabyte, gigantic, gigantopithecus
γλήνη gleno- eyeball socket glenoid, glenohumeral, euglena, infraglenoid
γλοιός glia- glue glia, glial, glioma, neuroglia, oligodendroglia, mesoglea
γλυκύς glyco-, gluco- sweet glycogen, glycolysis, glycerol, glycine, glycosidic, glucose, triglyceride, hypoglycemic, proteoglycan
γλύφω glyph- carving glyph, glyptic, glyptodon, petroglyph, hieroglyphic
γλῶσσα glosso- tongue, language glossary, glossopharyngeal, genioglossus, polyglot, glottis, epiglottis, hypoglossal, styloglossal
γναθμός gnatho- jaw gnathostome, gnathopod, agnathous, prognathism, opisthognathism, chaetognath
γνῶσις gno- to know gnosis, gnomon, agnosia, diagnosis, prognosis, stereognosis, agnostic, pathognomonic, physiognomy, recognize, cognizant, cognition
γονή gono- seed, offspring gonad, gonorrhea, archegonium, epigone, schizogony
γόνυ goni- angle, knee goniometer, gonion, gonarthritis, gonalgia, polygon, trigonal, diagonal, trigonometry, orthogonal, amblygonite
γράμμα gram- letter, writing gram, grammar, diagram, histogram, electrocardiogram, parallelogram, program, monogram, tetragrammaton
γράφω graph- engraving, drawing graphic, graphite, graffiti, agraphia, dysgraphia, biography, radiograph, paragraph, geography, topographical
γυμνόω gymno- naked, bare gymnasium, gymnast, gymnosperm
γυνή gyne- woman, wife, queen gynecology, gynecocracy, gynecomastia, gynandrous, gynoecium, misogyny, androgyny
γῦρός gyro- ring, coil gyro, gyrate, gyroscope, gyrus, gyri, gyral, oculogyric, spirogyra

Δ δ delta

The capital delta is shaped like a triangle, Δ, and this Greek letter is found in the names of triangular structures such as a deltoid wing, deltoid muscle, or the Nile delta. This letter is also a symbol for difference or change, such as ΔH in chemistry, or Δy/Δx (also known as slope). The lower case delta, δ, is also used as a derivative symbol in calculus to represent a very small difference (the slope of a curve at one point). In geometry, a deltoid curve is a hypocycloid with three cusps, and δ is often used to label the fourth angle of a quadrilateral (the others, of course, being α, β, and γ) .

Root Stem Meaning Examples
δάκτυλος dactyl- finger, toe dactyl, dactylitis, pentadactyl, syndactyly, polydactyly, pterodactyl, artiodactyla, perissodactyla
δεκά deca- ten decade, decalogue, decagon, decane, decapod, decalin, decathlon, dean, dodecahedron, undecane
δέλτα delta- Δ-shaped, triangular delta, deltoid, deltohedron, deltidium
δένδρον dendro- tree, branch dendrite, dendrochronology, oligodendroglioma, philodendron, rhododendron
δέρμα derma- skin, leather dermatology, dermatophyte, mesoderm, epidermis, pododerm, pachyderm
δεσμός desm- band, bond, ligament desmosome, syndesmosis, plasmodesmata, arthrodesis, pleurodesis
δεύτερος deutero- next, second deuterostome, deuterium, deuteranopia, deuteronomy, deuteroscopy
δῆμος demo- people, public demotic, demography, demagogue, democracy, epidemic, endemic, pandemic
διά dia- across, apart dialogue, diagnosis, diabetes, dialysis, diameter, diagonal, diagram, diabolical, diastole, diapedesis
δίσκος disk- round plate disk, disc, diskette, discus, discobolus, discotheque, disco, discoid, dish
δίψιος dipsi- thirsty, dry adipsy, dipsomania, polydipsia
δολιχός dolicho- long dolichocephalic, dolichorrhine, dolichocerous, dolichurus
δόξα dox- opinion, teaching docent, docile, doctor, doctrine, document, dogma, doxology, orthodox, paradox, heterodox
δόσις dote- give dose, dote, anecdote, antidote, apodosis
δρόμος drome- running, course syndrome, prodrome, hippodrome, palindrome, loxodrome, anadromous, dromedary
δύναμις dynam- ability, power, energy dyne, dynamic, dynamo, dynamite, dynasty, aerodyne, hemodynamics, hydrodynamics, thermodynamics
δύο, δίχα di- two, double, both digon, dichotomy, dichasium, diplococcus, diploid, diploma, diplomat, dyad
δύς dys- difficult, abnormal dysfunction, dyslexia, dyspepsia, dysuria, dysentery, dysphagia, dyscrasia, dysgenesis, dystrophy, dysplasia, dysmorphic
δώδεκα dodeca- twelve dodecane, dodecagon, dodecahedron, dodecahedrane, dodecaphonic, duodenum

E ε epsilon

The epsilon is one of the two letters to represent the E vowel in ancient Greek (eta, η, is the other). Since Greek lacked an H, breath marks over the vowel are used to indicate whether an "h" sound should be pronounced. Therefore, many of these word roots begin with H in English and some, like esophagus and ether, were initially begun with other vowels (oesophagus, aether). These spellings have been simplified, but are still used in some words like amoeba. Check word roots beginning with alpha and omicron for more English words beginning with that began with an epsilon in Greek. The medieval lunate epsilon, ϵ, has come to symbolize the elements of a set, while the Greek epsilon, ε, has become the symbol for average kinetic energy.

Root Stem Meaning Examples
ἓδρα hedra- seat, base dihedral, polyhedron, tetrahedral, octahedral, cathedral, ex cathedra, ephedrine
ἒθνος ethno- nation ethnic, ethnicity, ethnobotany, ethnography, ethnomusicology
ἒθος etho- custom, moral ethos, ethic, ethical, ethology
εἶδος eido- shape, form eidetic, kaleidoscope, idea, ideology, idol, idyll, adenoid, ovoid, ellipsoid, spheroid, amyloid, lymphoid, cushingoid
εἶκοσι eicosa- twenty eicosane, eicosanoid, icosahedron, icosagon
ἐκ, ἐξω exo-, eka- out of, from outside exoskeleton, exogenous, exodus, exocrine, exotic, ekasilicon, ekaluminum
ἑκατόν hecta- hundred hecatomb, hectometer, hectare
ἐκτός ecto- outside, removal ectoderm, ectopic, ectothermic, ectomorph, ectasia, bronchiectasis, embolectomy, appendectomy, mastectomy, splenectomy, vasectomy
ἔλασις elasti- impulsive, driven elastic, elasticity, elastin, elastase
ἑλμινς helminth- worm helminthic, helminthology, platyhelminthes, antihelmintic
ἔμετος emeti- vomit emesis, emetic, emetine, hematemesis, hyperemesis
ἐν endo- in, within, inner endoskeleton, endocrine, endoderm, endoscopy, endothelium, endogenous, endorphin
ἐννέα ennea- nine enneagon, enneagram, ennead, enneandrous, aeneid
ἔντερον entero- intestine, entrails enterohepatic, enterolysis, archenteron, dysentery, mesentery, exenterate, myenteric, gastroenteritis, coelenterate, parenteral
ἕξ hexa- six hexagon, hexagram, hexane, hexose, hexahedron, hexadecimal, hexameter, cyclohexane
ἐπί epi- upon, above, aside epicycle, epicenter, epinephrine, epidemic, epidermis, epilepsy, epididymis, epidural, epigenesis, epiglottis, epimysium, epiphyte, episode, epistaxis, epitaph, epithelia, epitome, eponym, epoxy
ἑπτά hepta- seven heptagon, heptane, heptadecagon, heptad, hebdomad
ἔργον ergo- work, tool erg, ergonomic, energy, argon, organ, allergy, adrenergic, cholinergic, dramaturge, exergonic, metallurgy, surgery, surgeon, synergy
ἑρπετόν herpeti- creeping herpes, herpetic, herpetology
ἔρρω erra- wander, be lost err, erratic, erratum, erroneuous, error, errand, errant, aberration
ἐρυθρός erythro- red erythrocyte, erythema, erythematous, threonine, hemerythrin
ἔρως ero- love eros, erotic, erogenous, erotomania, autoerotic
ἕτερος hetero- one of two, different heterodox, heterochromic, heterodont, heterogamy, heterosexual, heterogeneous
ἔτυμος etymo- true meaning, word origin etymology, etymon
εὖ eu- proper, true eukaryote, euphoria, euphonious, eucharist, eugenics, eulogy, euthanasia, euglena, euphemism, aneuploidy, utopia
ἐχῖνος echino- spiny, hedgehog echinoderm, echinococcus, echinocyte, echidna

Z ζ zeta

In Greek, the letter z comes early in the alphabet and provides the pronunciation for the letter in Spanish (zeta) and British English (zed). In quantum chemistry, capital Z is the symbol for effective nuclear charge (on an electron). The Riemann zeta function is thought to relate to the distribution of prime numbers, and is an active area of research in mathematics.

Root Stem Meaning Examples
ζεῦγος zygo- yoke, paired, union zygote, zygomatic, zygodont, zeugma, zeuglodon, zeugopod, monozygotic, dizygotic, azygos, syzygy, yoke, yoga, jugular
ζῆλος zeo- boil, fervor zeal, zealot, zeolite, eczema
ζὖμη zym- ferment, leaven zymosis, zymurgy, zymase, enzyme, lysozyme, ribozyme
ζωή zo- animal, life zoo, zoology, zoonotic, zodiac, zoetrope, azo, azotemia, epizootic, metazoan, protozoa, paleozoic, mesozoic, cenozoic
ζώνη zono- belt, girdle zone, zona, zoning, zonohedron, zonula

H η eta

Classical Athenians voiced the eta, producing an e sound. As a result, we use an e to spell some Greek words beginning with η (such as electron; see ε for other examples). However, the ancient Greeks living on the Italian peninsula pronounced this letter voicelessly (like our h sound), which may be the origin of H in the Latin alphabet. In chemistry, a capital H stands for enthalpy (not heat). In fluid dynamics, a lower case η is the symbol for viscosity. Many of the roots listed here were spelled using other vowels, but have adopted the initial letter h in their translation to English.

Root Stem Meaning Examples
ἡδονή hedon- pleasure, delight hedonics, hedonist, hedonism, anhedonia
ἡέλιξ helico- spiral, coil helix, helical, helicobacter, helicopter
ἠθμός ethmo- sieve ethmoid, ethmose, nasoethmoidal
ἤλεκτρον electro- amber, sparks electricity, electron, electrode, electronics, electrokardiogram, electroencephalogram, dielectric, piezoelectric
ἡλιος helio- sun helium, heliotrope, heliotropism, heliocentric, aphelion, perihelion
ἡμί hemi- one-half hemianopsia, hemisphere, hemiplegia, hemiballismus, heminephrectomy
ἠοῖος eo- dawn, early age, rosy eosin, eosinophil, eocene, eohippus
ἧπαρ hepato- liver hepatitis, hepatic, hepatoma, hepatology, heparin

Θ θ theta

The Greek theta is a single letter for a sound that requires two letters in English — th. Many English words that start with this sound come from Greek (e.g. thesis, theory, theology). In Ancient Greece, it was the symbol for death (thanatos) and used as a warning, similar to a skull-and-crossbones. It may have been intended as such on the original Earth Day flag, where it symbolizes a planet in peril. To most students, however, the lower case theta is familiar as a variable for plane angle measurements, especially central angles of the unit circle. Perhaps this is because the symbol for theta resembles a circle with its diameter drawn.

Root Stem Meaning Examples
θάλαμος thalamo- chamber, bedroom thalamus, thalamic, hypothalamus, epithalamus, spinothalamic
θάλασσα thalasso- ocean, sea water thalassemia, thalassian, thalassophobia, thalassotherapy
θαλλός thallo- young plant, sprout thallus, prothallus, thallium, thallate
θάνατος thanato- death thanatos, thanatology, thanatophobia, thanatoid
θεῖον thio- sulfur, brimstone thiol, thiourea, thioether, thiobacteria, thiocyanate, methionine
θέμις thema- position, law theme, thematic, apothem, anathema
θεός theo- god, deity theology, theobromine, theocracy, apotheosis, atheist, enthusiasm, pantheon, polytheism, monotheism, deity
θερμός thermo- heat thermometer, thermophile, thermos, thermal, thermostat, hypothermia, poikilotherm, endotherm
θέσις theti- arrangement, proposition thesis, synthesis, antithesis, diathesis, metathesis, hypothesis, parenthesis, prosthesis, prosthetic, epithet
θήκη theca- case, sheath, box theca, thecodont, apothecary
θηλή theli- nipple, suckling thelion, thelarche, epithelium, endothelial, mesothelioma, myoepithelial, thelaziasis
θήρ thera- wild beast, hunt therapsid, theropod, eutheria, dinothere, titanothere
θιγγάνω thigmo- touch, reach thigmotactic, thigmotropic, thigmesthesia, thixotropy
θρόμβος thrombo- lump, blood clot thrombus, thrombosis, thrombogenic, thrombocyte, thromboxane, thrombophlebitis
θὖλακος thylaco- sack, pouch thylacine, thylakoid
θῦμός thymo- heart, soul, courage, will thymus, thymic, thymidine, thymectomy, dysthymia, cyclothymia, hypothymic
θυρεός thyro- shield, thyroid thyroid, thyroxine, thyrotoxicosis, triiodothyronine
θώρᾶξ thoraco- breastplate, chest thorax, thoracic, thoracotomy, thoracoabdominal, hemothorax, pneumothorax, hydrothorax, chylothorax

I ι iota

The lower case iota is the smallest letter in the Greek alphabet and is used to mean a "tiny bit" as in the expression not one iota. It sometimes appears under other vowels in Greek (such as ᾳ, ῃ or ῳ); this iota subscript modifies the pronunciation of the vowel. Iota has given rise to the Latin letter i, which has come to symbolize the imaginary unit of complex numbers.

Root Stem Meaning Examples
ἰᾶτρός iatro- physician, treatment iatrogenic, psychiatry, pediatrics, geriatrics, physiatry
ἰδέᾶ ideo- form, way, idea idea, ideology, ideograph, ellipsoid
ἴδιος idio- peculiar, one’s own id, ides, idem, ibid., identity, idiopathic, idiot, idiom, idiotype, it
ἴκτερ ictero- jaundice icterus, icteric, kernicterus
ἰνίον ino- nape of neck, sinew inositol, inotropic, inion, exine
ἴον iodo- violet iodine, iodopsin, iodophore, radioiodine, triiodothyronine
ἶός ion- to go, arrow ion, ionic, ionizing, anion, cation, carbon, neon, sodium, dysprosium
ἵππος hippo- horse hippodrome, hippopotamus, hippocampus, hippopede, hippurate, eohippus, Philip
ἶρις irido- rainbow, iris of eye iris, iridectomy, iritis, iridium, iridescent, iridokinesia
ἰσθμός isthm- narrow passage isthmus, isthmic, paristhmic
ἴσος iso- same, equal isosceles, isomer, isotope, isobutane, isogamy, isobar, isometric, isomorphism, isocracy
ἱστός histo- ship’s mast, web, loom, tissue histology, histamine, histidine, histone, histochemistry, histopathology, histoplasmosis, histiocyte, histogram
ίσχίον ischia- hip socket ischium, ischial, sciatic, sciatica, saurischia, ornithischia
ἴτης -itis inflammation, insolence appendicitis, arthritis, arthritides, colitis, dermatitis, gastroenteritis, prostatitis, tonsillitis, typhlitis
ἰχθὖς ichthy- fish ichthyology, ichthyosis, ichthyosaur, osteichythes, chondrichthyes

K κ kappa

The Greek letter kappa was translated to the hard C sound in the Roman alphabet. In the middle ages, the Romance languages shifted to the softer s pronunciation for C followed by certain vowels but remained hard in Germanic languages. Thus, the Roman name Caesar translates to the German word Kaiser . The abbreviation for electrocardiogram is EKG because the word came to English from Greek through German. Lower case kappa represents curvature in mathematics, and a class of antibody light chains in immunology.

Root Stem Meaning Examples
καινός ceno- new, empty, unheard of cenozoic, cenotaph, kainite, eocene, pleistocene, oligocene, recent
κακός caco- bad, useless, unfit, wicked cacophony, cacography, cacology, cacodemon
καλέω cale- call, summon calendar, calendrical, calendula, kalends
καλός kale- beautiful, fair kaleidoscope, kalium, hyperkalemia
καρδίᾶ cardio- heart, soul cardia, cardiac, cardiovascular, cardioid, pericardium, electrokardiogram, myocardial, dextrocardia, bradycardia, tachycardia
καρκίνος carcino- crab, cancer carcinoma, carcinogen, carcinoid, adenocarcinoma
καρπὁς carpo- wrist, pluck, fruit carpus, carpal, carpel, carpet, excerpt, metacarpal, endocarp, pericarp, carpe diem
κάρυον karyo- nut, kernel, nucleus eukaryote, prokaryote, karyotype, megakaryocyte, synkaryon
κατά cata- flow down, decrease catabolism, cathode, cation, cataclysm, catarrh, catheter
καῦσις caus- burn caustic, encaustic, causalgia, holocaust
κελή cele- swelling, hernia keloid, blastocele, cephalocele, cystocele, myelocele, omphalocele, hydrocele, galactocele, pneumatocele, ureterocele, varicocele
κέντρον cente- center point, puncture center, central, centriole, centrifuge, centrosome, centrist, concentric, eccentric, amniocentesis, paracentesis, thoracentesis
κέρας kera- wax, horn cere, keratin, ceruminous, kerosene, adipocere, triceratops, rhinoceros, chelicera, karat, carob
κέρκος cerco- tail cercopithecidae, cysticercus, heterocercal, metacercaria, onchoceriasis, plerocercoid
κεφαλή cephalo- head cephalic, cephalopod, cephalization, hydrocephalus, telencephalon, enkephalin, anencephaly, encephalitis, dolichocephalic
κῖνέω kine- motion, activation kinetic, kinesthesia, kinin, kinase, kinesiology, kinematics, cinema, cinematography, cytokine, cytokinesis, dyskinesia, hyperkinetic, telekinesis
κλάδος clado- branch clade, cladogram, cladistics, cladophyll, heterocladic
κλάσις clast- breaking clastic, osteoclast, iconoclast, pyroclastic
κλείς cleido- key, bolt, clavicle cleidoic, hypocleidium, sternocleidomastoid, craniocleidodysostosis
κλἶνω clino- slope, lean, recline clinic, clinical, clinician, incline, inclination, decline, recline, anticline, triclinic, monoclinic, climax, climate
κλόνος cloni- spasm, turmoil clonic, clonus, opsoclonus, myoclonus, myoclonic, clonidine
κλύζω clysi- wash cataclysm, enteroclysis, hypodermoclysis, venoclysis
κοῖλος coelo- hollow, cavity coelom, coelomic, schizocoely, pseudocoelomate, coelacanth, coelenterate, blastocoel, celiac
κόκκος cocco- berry coccus, cocci, coccolith, coccidiosis, cryptococcus, diplococcus, pneumococcal, streptococcal, meningococcemia, cochineal
κόκκῦξ coccy- cuckoo’s beak coccyx, coccygeal, coccydynia, geococcyx, cuckoo, cuckold, kook
κόλλᾶ colla- glue, stick together collagen, colloid, collate, collection, collective, colligative, collodion, protocol
κόλος colo- colon, curtailed, bent, stump-horned colon, colic, coliform, colectomy, colostomy, colitis, E. coli, scoliosis
κόλπος colpo- fold, bosom, vagina colpitis, colposcopy, colpocele, endocolpitis
κόνδυλος condylo- knuckle, knob condyle, condylar, condylarth, condyloma, epicondyle, intercondylar
κονἶω conio- dust condium, conidiophore, hemoconia, pneumoconiosis, koniscope, konimeter, androconium
κοπρίᾶ copro- dung, feces coprolite, coprophagy, coprolalia, coprodeum
κόραξ coraco- crow, raven coracoid, coracohumeral, coronoid
κόρη core- doll, pupil of the eye corediastasis, corelysis, polycoria, anisocoria
κόσμος cosmo- ordered world, universe cosmos, cosmology, cosmopolitan, microcosm
κόχλος cochle- shell, snail cochlea, conch, conchae, conchoid, conchiolin, concholog, cochlite, cockle
κρᾶνίον cranio- skull cranium, cranial, craniosynostosis, chondrocranium, hemicranium, pericranium, olecranon, migraine
κρέας creato- flesh, meat creatine, creatinine, creosote, creodont, pancreas, crude, cruel
κρἶνω crino- secretion, separation crinin, endocrine, exocrine, apocrine, eccrine, holocrine, amacrine, paracrine, neurocrine
κρίσις criti- judgment, dilemma crisis, critic, critical, criterion, hypocrite, diacritic, hematocrit
κρύος cryo- ice, frost, crystal crystal, crystalline, crystalize, crystallography, cryogenics, cryoprecipitate, cryoglobulin, cryosurgery, cryotherapy
κρυπτός crypto- hidden, concealed crypt, cryptic, cryptogenic, cryptorchism, cryptobiosis, cryptography, krypton, encryption
κύανος cyano- blue, blue-green cyanide, cyanosis, cyanotic, cyanobacteria, cyanophyte, cyanophyll, cyanotype, cyanocobalamin, hemocyanin
κυβερνάω cyber- steerer, helmsman, computer cybernetic, cybernaut, cyborg, cyberspace, cyber café, gubernatorial, government
κύβος cubo- cube cube, cubic, cubicle, cuboidal, cuboctahedron, cubism
κύκλος cyclo- circle, wheel cycle, cyclic, cycloid, cyclosis, cyclooxygenase, cyclone, cyclothymia, bicycle, epicycle, encyclical, chakra
κυλίνδω cylindro- roll, cylinder cylinder, cylindrical, calendar
κῦμα kymo- wave, swell kymation, kymograph, cyma, pseudocyesis
κυρτός kurto- curved kurtosis, kurtotic, leptokurtic, mesokurtic, platykurtic
κύστις cysto- bladder, bag cyst, cystic, cysteine, cystitis, cystoscopy, nematocyst, polycystic
κύτος cyto- hollow space, cell cytosine, cytology, cytoplasm, cytomegalovirus, hemocytometer, oocyte, phagocytosis, immunocytochemistry, erythrocyte, leukocyte, osteocyte, polycythemia, syncytium, astrocytoma, pancytopenia
κῦφός kypho- bent kyphosis, kyphoscoliosis, kyphotic
κύων cyno- dog cynic, cynosure, cynocephalic, cynophobia, cynopodous, cynodont, procyon
κῶμος coma- revelry, hangover, stupor coma, comatose, comedy, comedian, comic
κώνος cono- cone conic, cone, conus, conifer, triconodont

Λ λ lambda

The Greek lambda, λ, is the symbol for the wavelength of light and other forms of electromagnetic radiation. In anatomy, the lambdoid suture is the Λ-shaped joint between the occipital and parietal bones of the skull. The lambda phage is a virus that injects its DNA into bacteria — a useful tool for genetics research.

Root Stem Meaning Examples
λαβύρινθος labyrinth- maze labyrinth, labyrinthine, labyrinthitis, labyrinthodon
λαπάρη lapa- abdomen, loins, belly lap, laparotomy, laparoscopy, laparorrhaphy
λάρυγξ laryngo- gullet, larynx laryngeal, larynx, laryngectomy, otolaryngology
λεῖος leio- smooth, hairless leiomyoma, leiomyosarcoma, leiotrichous
λείψανον lipse- lack, fall short, remnant ellipse, elliptical, ellipsis, eclipse
λέκιθος lecitho- egg yolk lecithin, alecithal, isolecithal, microlecithal, macrolecithal
λέμμα lemma- sheath, peel, husk lemma, lemmocyte, dilemma, sarcolemma, neurolemma, oolemma
λεπτός lepto- thin, light, delicate leptin, lepton, leptomeninges
λευκός leuko- clear, white, pale leukocyte, leukoplakia, leukemia, leucine, isoleucine
λίθος litho- stone, marble lithotomy, lithotripsy, lithograph, lithium, otolith, monolithic, neolithic, megalith, nephrolithiasis, cholelithiasis
λίνον lino- linen, thread, line line, linear, lineage, linotype, collinear
λίπος lipo- fat, oil lipid, lipase, liposuction, lipocyte, lipodystrophy, aliphatic, synalepha
λοβός loba- lobe lobe, lobar, lobular, lobule, lobotomy
λόγος logo-, -logy discourse, study, word logic, logistics, logorrhea, logarithm, dialogue, homology, analogy, apology, cardiology, neologism, syllogism, teleology, antilog
λύκος lyco- wolf lycanthrope, lycopodium, lycopene
λύσις lys- loosening lysis, lysogeny, lysosome, lysine, lytic, lyophilic, hemolytic, analysis, dialysis, enterolysis, catalysis, hydrolysis, paralysis, electrolysis, electrolyte

M μ mu

Our letter M translates to the Greek mu, μ. A lower case μ is the symbol for the prefix micro- meaning one-millionth or, by itself, the micrometer or micron — a useful unit of measure at the cellular level. Upper case M symbolizes the prefix mega- used as a million multiplier. The Greek alphabet itself uses these word roots in the names of its two O vowels: omicron and omega. In mathematics, a lower case mu is the symbol for the mean of a normal distribution.

Root Stem Meaning Examples
μάθημα math- mental discipline, learning mathesis, mathematics, math, mathematician, polymath, chrestomathy, mathlete
μακρός macro- large, long macro, macron, macroevolution, macroeconomics, macroglossia, macrocytosis, mecopteran, paramecium
μαλακός malaco- soft, weak malacology, malacostracan, chondromalacia, osteomalacia, leukomalacia, mollusk, mollify, melt
μανίᾶ mania- rage, madness mania, manic, egomaniac, beatlemania, kleptomania, megalomania, monomaniacal, pyromania, trichotillomania
μάσσω massa- kneaded dough, mouthful mass, massive, biomass, amass, masseter, macerate, mastication, magma
μαστός masto- breast, nipple mastectomy, mastitis, mastodon, mastoid, gynecomastia, sternocleidomastoid
μέγας mega- large, million megalomania, megabyte, megaphone, megalith, megaton, megatrend, megabucks, megadeath, acromegaly, hepatomegaly, omega
μέθη methy- wine, drunkenness methane, methyl, methylene, methionine, methanol, amethyst
μέλᾶς melano- black, dark melancholy, melanin, melena, melanism, melanoma, melanophore, melanesia
μέρος mero- part, portion merocrine, meristem, sarcomere, monomer, polymer, dimerous, telomere, centromere
μεσόω meso- in the middle mesoderm, mesothelium, mesocarp, mesentery, mesopotamia
μετά meta- beside, beyond metamorphosis, metabolism, metacognition, metaphase, metaphysis, metacarpal, metatarsal
μέτρον metro- measure, prime of life, womb metric, meter, perimeter, geometry, metrology, metronome, endometriosis, myometrium, symmetry, metropolis, metro
μήν men- month, moon menarche, menopause, menstruation, menorrhagia, meniscus, meniscectomy, amenorrhea, catamenia, dysmenorrhea, moon, month
μήνιγξ meningo- membrane meninges, meningeal, meningitis, meningococcemia
μηχανή mechano- device, artificial instrument machine, mechanic, mechanical, mechanism, mechanization, mechanoreceptor, biomechanics, magus, magic
μῖκρός micro- small micron, microscope, microbe, microfilm, microfiche, microevolution, microlithiasis, micromelia, omicron
μἶμημα mime- imitate, copy, actor mime, mimic, mimicry, mimetic, mimeograph, imitation
μίτος mito- thread mitochondrion, mitosis, mitotic, mitogen, mitomycin
μνήμη mne- memory mnemonic, amnesia, amnesty, catamnesis, anamnesis
μόνος mono- single, alone monad, monastery, monomial, monosaccharide, monocyte, mononucleosis, monotone, monk, pseudomonad
μορφή morpho- form, shape metamorphosis, morphology, dimorphic, enantiomorph, anthropomorphic
μουσικός muse- music, muse muse, museum, music, mosaic, amusement
μυελός myelo- marrow, spinal cord myelin, myeloblast, myelocyte, myelocele, hydromyelia, syringomyelia, poliomyelitis, osteomyelitis
μύκης myco- fungus, mushroom mycology, mycetoma, actinomycosis, neomycin, streptomycin, onychomycosis
μυξτήρ myxo- snot, snout, mucus myxoid, myxoma, myxomatous, myxamoeba, myxine, myxomycete, polymyxin
μυριάς myria- numberless, 10000 myriad, myriapod
μύρμηξ myrmeco- ant myrmecophagy, myrmecophobia
μῦς myo- muscle, mouse myocyte, myofibril, myosin, myositis, myotomy, perimysium, mysticeti

N ν nu

The Latin letter N translates to the Greek letter nu, ν, the symbol for the frequency of a wave of light or other electromagnetic radiation. Thus the symbol for a photon of light is , the product of Planck's constant and frequency. Lower case nu is also the symbol for the neutrino, an elementary atomic particle. The nu-movable is the letter ν added to the end of certain Greek words when the following word begins with a vowel, just as in English a becomes an before an initial vowel.

Root Stem Meaning Examples
νᾶνος nano- dwarf, very tiny nanometer, nanotechnology, nanosecond, nanotube, nanofossil, nanoplankton
ναρκάω narco- numbness, stupor narcotic, narcosis, narcolepsy, narc, narcotize
ναῦς nauti- ship, sailing nautilus, nautical, astronaut, argonaut, cosmonaut, nausea, noise
νεκρός necro- dead, corpse necrosis, necrotic, necrotizing, necropsy, necropolis, necromancy, pernicious
νέος neo- new, young neoplasm, neophyte, neologism, neoclassic, neolithic, neon, gluconeogenesis
νευρἆ neuro- nerve, sinew, cord neuron, neurology, neuroanatomy, neurosyphylis, neurotic, aponeurosis, perineurium
νεφρός nephro- kidney nephron, nephrolithiasis, nephridium, nephrology, neprhoid, epinephrine, perinephric, hydronephrosis, metanephrine, pronephros
νῆμα nema- thread nematode, nematocyst, chromonema, myoneme, axoneme, treponema
νήχω nek- swim nekton, nektonic
νιτρή nitro- soda, nitrogen nitrous, nitric, nitrogen, nitrate, nitrate, nitrify, denitrification
νόμος nomo-, -nym name, usage, rule, law nomology, anomie, economy, astronomy, deuteronomy, metronome, numismatic, anonymous, pseudonym, eponym, homonymous, onomatopoeia, patronym, synonym
νύμφη nymph- bride, maiden, nuptial nymph, nymphomania, nymphiparous, nymphitis
νῶτον noto- the back notochord, notanencephalia, notobranchial, stenonotal

Ξ ξ xi

While few English words begin with x, most of the ones that do are derived from Greek words beginning with the letter xi, ξ.

Root Stem Meaning Examples
ξανθός xantho- yellow xanthophyll, xanthoma, exanthem
ξένος xeno- stranger, guest xenograft, xenophobia, xenon, xenogamy, xenobiosis, antixenic, euxenite, pyroxene
ξηρός xero- dry powder xerophyte, xerox, xeric, xerostomia, elixir
ξίφος xipho- sword xiphus, xiphoid
ξύλον xylo- wood xylem, xylene, xylophone, xylophyte, xylophagy, metaxylem

O o omicron

The Greek omicron has a short "o" sound (as in the English word "pot") and the name omicron literally means micro or "short o" while the other Greek vowel omega means "long o." The letter O is rarely used as a symbol in mathematics or science because of its resemblance to the number zero.

Root Stem Meaning Examples
ὀδούς odonto- tooth, tusk odontoid, odontoblast, odontogenic, odontoceti, orthodontist, glyptodont, mastodon
ὀδύνη odyno- pain, suffering odynophagia, pleurodynia, glossodynia, anodyne
οἶκος œco- house, abode ecology, economics, dioecious, diocese
οἶστρος œstro- madness, frenzy estrus, estrone, estrogen, estradiol, polyestrous
ὀκτώ octo- eight octagon, octopus, octuple, octane, octadecanoic, october
ὀλίγος oligo- few, scanty oligarchy, oligopoly, oligodendrocyte, oligonucleotide, oligosaccharide, oliguria
ὃλος holo- whole, complete, all hologram, holosystolic, holocaust, holoblastic, holoenzyme, holocrine, holometabolous, holotype, holostei
ὃμοῖος homo- same, alike homologous, homosexual, homophone, homeostasis, homogeneous, anomalous
ὀμφαλός omphalo- navel omphalos, omphalocele, omphalic, umbilical
ὀνκος onco- mass, swelling, tumor oncotic, oncology, oncocyte, oncogene, oncovirus, oncomouse
ὄντως onto- being, reality, existence ontology, ontogeny, paleontologist, symbiont, schizont
ὄνυξ onycho- claw, nail onychophagia, onychomycosis, onychophoran, onycholysis, onyx, paronychia
ὀξύς oxy- sharp, sour, acid oxidation, oxygen, oxymoron, oxalis, oxidation, oxygenation, oxytocin, oxyacetylene, anoxia, deoxyhemoglobin, hydroxide, paroxysm, amphioxus
ὀπίσθιος opistho- hind, back opisthobranch, opisthion, opisthodont, opisthognathous
όπός opio- juice of plants opiate, opium, opioid
όπτήρ opti- appearance, sight optic, optician, rhodopsin, autopsy, synopsis, optometry, diopter, diplopia, myopia, presbyopia, amblyopia
ὄργανον organ- instrument, tool organ, organism, organize, organization, organic, organelle, orgasm
ὀρθός ortho- straight, upright orthodox, orthodontia, orthopedics, orthogonal, orthocenter
ὄρνις orni- bird ornithology, ornithomimus, archaeornis, aepyornis, ichthyornis
ὄρχις orchi- testis orchidectomy, orchitis, orchid, clonorchis, cryptorchidism
ὀς -osis possession, symptom, condition diagnosis, diagnoses, miosis, ptosis, anhidrosis, psychosis, neurosis, hypnosis, osmosis, diverticulosis
ὀσμή osmo- smell, odor osmosis, osmolarity, osmoregulation, anosmia, chemiosmotic, ozone
ὀστέον oste- bone, hard shell osteon, osteology, osteoblast, osteophyte, osteopath, os, osseous, ossicle, ossuary, ossify, periosteum, exostosis, synostosis, teleost, ostracod, ostracize, oyster
οὔρἆ ouro- tail, urinary urology, urea, urine, uracil, urosepsis, ureter, urethra, diuretic, dasyure, dysuria, hematuria, anuran, cynosure, trichuriasis, squirrel
οὐρανός ourano- heaven, firmament uranus, uranography, uranium, uranite
ὀφθαλμός ophthalm- eye ophthalmology, ophthalmic, exophthalmos, microphthalmos, xerophthalmia

Π π pi

Lower case pi is the symbol for the transcendental number that describes the ratio of a circle’s perimeter to its diameter. The pi function finds the number of prime numbers below a given integer, for example π (100) = 25 because there are 25 prime numbers less than 100. In chemistry, a pi bond is formed from overlapping electron orbitals in multiple covalent bonds. Upper case Π indicates the product of numbers in a sequence.

Root Stem Meaning Examples
πάθη patho- suffering, grief, disease pathos, pathetic, pathology, pathogen, pathognomonic, apathy, antipathy, empathy, idiopathic, sympathetic, parasympathetic, neuropathy, sociopath
παιδείᾶ paido- children, education pedagogy, pediatrics, pedomorphic, orthopedic, lithopedion, encyclopedia, wikipedia
παλαιός paleo- ancient paleontology, paleolithic, paleozoic, paleobotany, paleocortex
πάλιν palin- backwards, again palindrome, palingenesis, palinode, palimpsest
πάν pano- all pandemic, panorama, panacea, panic, pancolitis, pancreas, pantograph, pantheism, pantheon, pandemonium, pancratium
παρά para- beside, along par, parallel, parallelogram, parabola, paramedic, paradox, parasite, parotid, parentheses, parody, pair, comparison
πάρεσις paresi- letting go, forgiveness, paralysis paresis, paretic, hemiparesis, gastroparesis
παρθένος partheno- virgin, maiden parthenogenesis, parthenocarpy, parthenon
πατρίς patri- father patriot, patriarch, allopatric, sympatric, eupatrid, Patrick
παχύς pachy- thick pachyderm, pachymeninges, pachytene, pachyglossus
πεῖρα peira- experience pirate, empirical, empiricism, experience, experiment, expert
πέλαγος pelago- open ocean pelagic, archipelago
πενίᾶ penia- poverty, need neutropenia, neutropenic, thrombocytopenia, osteopenia
πέντε penta- five pentagon, pentacle, pentagram, pentomino, pentane, pentadactyl, pentateuch, pentecost, pentameter
πεπαίνω pepti- digest, ripen, cook pepo, pepsin, peptic, peptide, peptone, eupeptic, dyspepsia, polypeptide, pumpkin
περί peri- around, superfluous perimeter, peripheral, periodontal, peripatetic, period, periscope, perineum, perissodactyl
πέτρᾶ petro- stone, rock petrify, petrous, petrobasilar, petroleum, peter, petroglyph, osteopetrosis, saltpeter, Peter
πηκτός pecto- fasten, fix, coagulate pecten, pectin, pectineus, pectineal, pectinate, pegmatite, areopagus, orchiopexy, hysteropexy, mastopexy
πίθηκος pitheca- ape pithecanthropus, australopithecus, cercopithecidae
πἶπτω pto- falling, drooping ptotic, ptosis, ptomaine, peripeteia, proptosis, symptom, asymptomatic, asymptote
πίσος pisi- pea pisiform
πλάνη plano- wandering planet, aplanatic, plankton, interplanetary
πλάξ placo- flat placoid, placenta, leukoplakia, plaque
πλάσμα plasma- formed, molded plastic, plaster, plasma, dysplasia, hyperplasia, metaplasia, neoplasm, cytoplasm, chloroplast, rhinoplasty, toxoplasmosis
πλατύς platy- broad, flat plate, plateau, platitude, platykurtic, platycephalic, platyhelminthes, platypus, platyrrhine, platysma, platter
πλείων plio- folded, multiplied, more pliant, pleomorphic, pleiotaxy, pliocene, pleistocene, triple, multiple, quaruple, triploblastic, diploid, haploid, polyploid, tetraploid, diploma, diplomat
πλευρἆ pleura- flank, side, rib pleura, pleural, pleuritic, pleurisy, pleurodynia
πληγή plegi- stroke, shock, weakness plectrum, plexor, paraplegia, hemiplegia, quadriplegic, apoplexy, cataplexy, plague
πλῆθος pletho- full, more, crowded plethora, plethysmograph
πνεῦμα pneuma- air, breath pneumatic, pneumatocele, pneumonia, pneumothorax, pneumonectomy, pneumoencephalogram, apnea, tachypnea, amphipneustic
ποδός podo- foot podite, podium, podiatry, podagra, antipodes, lycopodium, octopus, platypus, pseudopod, cephalopod, polyp, parallelepiped
ποιέω poie- to make, create poem, poetic, onomatopoeia, pharmacopoeia, hematopoiesis, erythropoietin
ποικίλος poikilo- varied, mottled poikilotherm, poikilocytosis, osteopoikilosis
ποινή poena- payment, penalty punish, punitive, pain, penal, penalty, impunity, subpoena
πόλις polis- city, citizenry polis, politics, policlinic, acropolis, megalopolis, metropolis, cosmopolitan
πολύς poly- many, much polymer, polynomial, polygon, polyhedron, polygamy, polytheism, polyglot, polynesia, polyuria, polydipsia, polymorphism, polyp
πόρος poro- passageway, channel, pore pore, porous, poromeric, emporium, gonopore, Bosporus
πορφύρᾶ porphyro- purple porphyria, porphyrin, porphyrinuria
ποταμός pota- rushing water potable, potion, hippopotamus
πρᾶξις prax- exercise, action praxis, practice, practical, apraxia, pragmatic
πρεσβεύω presby- old, elder presbyopia, presbyesophagus, presbycusis, presbyterian
πρίσμα prism- something that has been cut prism, prismatic, antiprism
πρό pro- before, in front of pro, prologue, prokaryote, proboscis, prosopagnosia, promethean, prone, reciprocal
πρωκτός procto- butt, rectum proctology, proctostasis, proctodeum, cytoproct, entoproct
πρωτεύω proto- first, original protist, protean, protozoa, proton, protocol, prototype, protostome, protein, proterozoic
πτερόν ptera- wing pterodactyl, pterion, pterygoid, pteridology, chiroptera, helicopter, diptera, hymenoptera, coleopteran, archaeopteryx
πτὖω ptya-, ptui- spit, saliva, phlegm ptyalin, ptyalocele, hemoptysis, pyoptysis, pituitary
πῦγή pygi- buttocks, rump pygidium, pygostyle, uropygium, steatopygia
πύελος pyelo- trough, pelvis pyelitis, pyelonephritis
πύλος pylo- gateway pylorus, pylon, micropyle, apopyle, Thermopylae
πῦρ pyro- fire, inflammation, pus pyre, pyretic, pyrite, pyrotechnics, pyromania, pus, purulent, pyogenic, pyonephrosis, pyrimidine, pyruvate, pyrex, pyrrole, pyramid, bipyramidal

P ρ rho

The Greek letter rho looks like the Latin letter P, but is pronounced with an "rh" sound. Lower case ρ is the symbol for density, for Spearman's correlation coefficient (because r is used as the symbol for Pearson's correlation), and for the radius of a sphere when three-dimensional coordinates are used. Upper case Ρ is the usual symbol for momentum in physics. In molecular biology, the rho protein terminates RNA synthesis.

Root Stem Meaning Examples
ῥάβδος rhabdo- rod rhapsody, rhabdom, rhabdovirus, rhabdomyosarcoma, rhabdomyolysis, rhabdopod
ῥαφή rhaphi- seam, suture raphe, rhapsody, herniorrhaphy, dysrhaphism, staphylorrhapy, tenorrhaphy
ῥάχις rachi- spine, backbone rachitic, rachiotomy, rachiopagus, rachiodont, rachitomous, rickets
ῥέω rheo- flow, current rheology, rheostat, diarrhea, amenorrhea, gonorrhea, catarrh, rheumatism, rhyolite
ῥήγμα rhage- breaking, fracture, downfall hemorrhage, menorrhagia
ῥίζα rhizo- root rhizome, rhizotomy, rhizopoda, mycorrhiza, licorice
ῥἶς rhino- nose rhinitis, rhinoplasty, rhinovirus, rhinoceros, rhinencephalon, catarrhine
ῥόδον rhodo- rose, pink rhodopsin, rhododendron, rhodium, rhodonite
ῥόμβος rhombo- magic wheel, rhombus rhombus, rhomboid, rhombic, rhombohedron
ῥυθμός rhythm- rhythm rhythm, rhythmic, arrhythmia, biorhythm, eurhythmic, rhyme

Σ σ sigma

The Greek letter sigma is translated into English as the letter S. Lower case sigma is written ς at the end of a word, or σ in the middle. The lower case σ represents the standard deviation of a normal distribution. A sigma orbital contains the electrons shared by atoms in a covalent bond. Upper case Σ indicates the sum of numbers in a sequence. In human anatomy, the sigmoid colon is an S-shaped loop of intestine while a sigmoid function in mathematics produces an S-shaped curve, like the logistic growth curve.

Root Stem Meaning Examples
σάκχαρον saccharo- sugar saccharine, saccharide, saccharomyces, disaccharide, polysaccharide, oligosaccharide, sucrose
σάλπιγξ salping- trumpet salpingectomy, salpingitis, salpingotomy, urosalpinx, mesosalpinx, salpingopharyngeal
σαπρός sapro- rotten, putrid saprophyte, saprobiotic, saprogenic, saprotroph, saprophage
σάρξ sarco- flesh sarcous, sarcomere, sarcoma, sarcoidosis, sarcophagus, sarcopterygian, chondrosarcoma, osteosarcoma
σαύρᾶ sauro- lizard sauropsid, sauropod, dinosaur, tyranosaurus, brontosaurus, saurischia
σαφηνής sapheno- apparent, true saphenous, saphenectomy
σεισμός seism- shaking, earthquake seismic, seismology, seismograph, seismometer
σελήνη seleno- moon selenography, selenology, selenium, selenide
σῆμα sema- mark, sign, signal semaphore, semantic, semiotics
σήπω septi- rotting, putrefaction sepsis, septic, antiseptic, aseptic
σθένος stheno- strength, might asthenia, callisthenics, myasthenia, neurasthenia, hypersthenia
σίαλον sialo- saliva, spit sialogram, sialadenitis, sialolithiasis, sialagogue
σίδηρος sidero- iron siderite, siderophore, sideroblastic, hemosiderin
σκάφη scapho- bowl, boat, scooped out scaphoid, scapholunate, scapula, scapular, scoop, shape
σκέλος skele- leg, skeleton skeletal, isosceles, cytoskeleton, triskelion
σκληρός sclero- hard, scarred sclera, scleroderma, sclerotic, atherosclerosis, otosclerosis
σκοπός scope- watch, look scope, microscope, telescope, periscope, stethoscope, endoscopy, laparoscopic, horoscope, episcopal
σκότος scoto- darkness scotoma, scotopic
σοφίᾶ soph- wisdom, skill sophomore, sophisticated, sophistry, philosophy
σπάσμα spasm- involuntary convulsion spasm, spastic, antispasmodic
σπέρμα sperm- seed, spore, spread sperm, spermatic, spermatocyte, spermatozoon, gymnosperm, angiosperm, diaspora, spore, sporophyte, neurospora
σπλάγχνον splanchno- viscera splanchnic, splanchnocranium, splanchnopleure, splenic, spleen
σπόγγος spong- sponge spongiosum, spongy, spongiform
σπονδῦλός spondylo- vertebra spondylosis, spondylosis, spondylitis, lepospondyl, temnospondyl
σπόρος sporo- seed, sowing spore, sporadic, ascospore, sporotrichosis
στάλσις stal- contract, make compact peristalsis, anastalsis, systole, diastole, apostolic, epistle
στάσις stat- standing still static, statistics, stasis, astatine, metastasis, homeostasis, orthostatic, thermostat, hemostat, prostate, diastasis, ecstasy, system, epistemology, obstetrics
σταφυλή staphyl- bunch of grapes staph, staphylococcus, brachystaphyline
στέαρ stearo- solid fat, suet stearic, steatosis, steatorrhea, steatopygia, steer, tristearin
στενός steno- narrow stenosis, stenotic, stenography
στερεός stereo- solid, stiff, three dimensional steric, stereo, stereoscopic, steroid, steropticon, stereographic, stereochemistry, stereophonic, steradian, cholesterol
στῆθος stetho- chest stethoscope, mesostethium, sternum, retrosternal
στίγμα stigm- spot, prick, tattoo stigma, stigmata, stigmatic, astigmatism, stick
στοιχεῖον stoichi- element of knowledge stoichiometry, stoichiology, stichomythia, acrostic
στόμα stoma- mouth, gullet stomatitis, stomach, stomachion, stomodeum, stomatopod, gastrostomy, colostomy, nephrostomy, gnathostome, deuterostomia
στρέφω strobe- twist, turn strepsis, streptococcus, streptokinase, strophoid, strabismus, strobilus, stroboscope, strobe, apostrophe, boustrophodon, catastrophe
στρῶμα stroma- bed, cushion stroma, stromal, stromatolite
στῦλος stylo- pillar, column, stylus style, styloid, stylus, stylet, stylomastoid, stylopharyngeus, peristyle, stiletto
στύραξ styro- fragrant resin, gum styrax, styrene, polystyrene, styrofoam
σύν syn-, sym- with, together synthesis, symphysis, synagogue, synovial, syndicate, synchronize, synergy, symphony, symbiotic, symbol, symmetry, symptom
σφαῖρα sphero- ball, sphere sphere, spherical, spherocytosis, atmosphere, biosphere, stratosphere
σφήνον spheno- wedge sphenoid, sphenodon, alisphenoid, basisphenoid, spheniscan, sphenodon, sphenography
σφυγμός sphygm- pulse sphygmomanometer, sphygmograph, sphygmoid, sphygmophone
σχῆμα schema- form, shape schema, scheme, schematic
σχίζω schis- split, division schism, science, omniscience, schist, schistocyte, schistosomiasis, schizophrenia, schizocoely, schizogamy, gastroschisis
σχολή schol- leisure, discourse scholar, scholasticism, school, schooled, schoolwork, scholarship, scholium
σῶμα soma- body somatic, somite, autosome, chromosome, somatosensory, tomb

T τ tau

The Greek letter tau (rhymes with "cow") is translated into English as the letter T. The tau cross is an ancient religious symbol resembling this letter. Lower case τ is the symbol for torque, or rotational force, in physics as well as the tau lepton particle. In neurons, tau proteins are associated with microtubules.

Root Stem Meaning Examples
ταινίᾶ taen- band, ribbon, tendon tenia, taenia, hypotenuse, diplotene, polytene, tenosynovitis, tetanus
τάξις taxo- arrangement, order taxonomy, taxon, taxidermy, syntax, phototaxis, phyllotaxy, tactics
ταρσός tarsa- flat of the foot tarsus, tarsal, tarsier, metatarsal
ταῦρος tauro- bull taurus, taurine, toreador, taurocholic
ταύτῃ tauto- same, in this way tautology, tautomer, tautonym
τάχος tachy- speed tachometer, tachycardia, tachypnea
τέγος tegm- roof, covering, plate tegmen, tectum, tectorial, tectonic, integument, protection, detect, stegosaurus
τέλος telo- end, completion telomere, telophase, telogen, telolecithal, telomerase, telopeptide, teleology, teleost
τέρας tera- wonder, monster teratoma, teratogen, teratocarinoma, teratoid, karma
τέρμα term- end, limit, goal term, terminal, terminate, determine, determinant, indeterminate
τέσσαρα tetra- four tetrad, tetrapod, tetrahedron, tetracycline, tetrahydrofuran, tetralogy, tetragrammaton, tesseract, tessera, diatesseron
τέχνη tech- art, skill technical, technetium, technology, tectonic, architect
τῆλε tele- far off, distant telephone, television, telescope, telekinesis, telemedicine, telemetry, telencephalon
τίλλω tillo- tear one’s hair out trichotillomania, tillodontia
τόκος toco- childbirth tocolytic, tocopherol, tocology, oxytocin
τομός tomo- cut tome, tomography, atom, anatomy, epitome, dichotomy, microtome, dermatome, protome, entomology, lithotomy, diatom, tracheotomy, lobotomy, appendectomy
τόνος tono- tone, tension, stretch tone, tonic, tonoplast, catatonic, dystonia, hypertonic, isotonic, opisthotonus
τόξον toxo- arrow, poison toxic, toxin, toxicology, toxoplasmosis, toxoid, detox, cytotoxin, tetrodotoxin
τόπος topo- place topic, topology, topographic, topoisomerase, ectopic, isotope, polytope
τορέω toro- bore hole, doughnut torus, toroidal, torovirus
τράγος traga- goat tragus, antitragus, tragedy, tragic, tragacanth
τράπεζα trapeza- dining table trapeze, trapezoid, trapezius
τρῆμα trema- perforation, hole trauma, traumatic, barotrauma, monotreme, trematode, atresia
τρεῖς tri- three tridactyl, trigonal, tritone, triad, trichotomy, triploblastic, triskaidekaphobia, triskelion
τριβή tryp- rubbing, boring trypsin, trypanosome, tryptophan, tryptamine, tribology, diatribe, lithotripsy, chymotrypsinogen, trepanation, trephine
τρίχῖνος tricho- hair trichotillomania, trichocyst, trichomonas, trichinosis
τρόπος tropo- turning, flexible tropism, tropical, tropomyosin, tropocollagen, phototropic, psychotropic, heliotrope, atropos, atropine
τροφός tropho- nourish, food trophoblastic, hypertrophy, dystrophy, neurotrophic, autotroph, heterotroph
τροχός trocha- pulley, block-and-tackle troche, trochanter, trochlea, trochlear, trochocephalia, cephalotrocha
τύμπανον tympano- drum tympanum, tympanic membrane, tympani, tympanitic, hemotympanum, pharyngotympanic
τύπος typo- blow, strike, type typography, typing, karyotype
τῦρός tyro- butter, cheese tyrosine, tyramine

Υ υ upsilon

In English, when the letter Y serves as a vowel, it is likely to be in words derived from Greek spelled with the letter upsilon, (for example, in the word rhythm). Words that began with upsilon are often translated to "hy" in English, such as hypotenuse or hyperbola. The hyoid bone is a υ-shaped bone in the human skeleton.

Root Stem Meaning Examples
ὕάλος hyalo- glassy, transparent hyaline, hyaloid, hyalocyte, hyalogen, hyalitis, hyalograph
ὕβρις hybri- defiance of nature hubris, hybrid, hybridization, hybridoma
ὑγίεια hygie- health hygiene, hygienic, hygienist, hygieiology, hygieiolatry
ὑγρός hygro- moisture hygrometer, hygroma, hygroscopic, hygrology, hygrine
ὑδρᾶ hydro- water, sea-serpent hydra, hydrogen, hydrant, hydraulic, hydroxide, hydrophobic, hydrophilic, hydrodynamics, anhydrous, carbohydrate, dehydration, aldehyde, clepsydra, hydatid, utricle, dropsy
ὑμέναιος hymen- wedding, song, membrane hymen, hymn, hymnal, hymenoptera, tetrahymena
ὑπέρ hyper- over, above hyperactive, hyperbolic, hyperbola, hypercube, hyperspace, hypertonic, hypertension, hypertrophic
ὕπνος hypno- sleep hypnosis, hypnotic, hypnagogic, rohypnol
ὑπό hypo- under, beneath hypodermic, hypochondriac, hypoglossal, hypotenuse, hypothesis, hypsometry
ὗς hyos- boar, pig hyena, hyaenodon, hyoscamus, hyoscyamine
ὑστέρᾶ hystero- uterus, womb hysterectomy, hysteria, hysterosalpingogram, sonohysterogram
ὑψηλός hypsilo- U-shaped, high hypsilophodon, hypsiloid, hypsicephaly, hypsiconchous

Φ φ phi

The Greeks used the letter phi to spell words with a "ph" sound, such as philosophy. The lower case φ is used as a second variable for angle measurements (when θ is already in use), or as a symbol for the polar angle in a three-dimensional coordinate system. The upper case Φ is the symbol for the golden ratio, an irrational number approximately equal to 1.618.

Root Stem Meaning Examples
φάγος phago- eat, glutton phage, phagocytosis, macrophage, glucophage, autophagy, bacteriophage, esophagus, dysphagia, sarcophagus
φάλαγξ phalang- line in battle phalanx, phalanges, interphalangeal, metacarpophalangeal
φαλλός phallo- penis phallus, phallic, ithyphallic, phallocentric
φανερός phan- appearance, phase phantasm, phantom, phase, phenotype, phenomenon, phenol, phenyl, phenylalanine, epiphany, diaphanous, metaphase, anaphase, telophase, phosphene, sycophant, fantasy
φάος phaeo- daylight, dusk pheochrome, pheochromocytoma, pheomelanin, pheophytin
φάρμακον pharma- drug, poison pharmacology, pharmacy, pharmaceutical
φάρυγξ pharyng- cleft, throat, gully pharynx, pharyngeal, oropharynx, glossopharyngeal
φάσις phase- speech, assertion dysphasia, aphasia, emphasis, prophet
φέρω phoro-, phero- carry, bear philosopher, periphery, euphoria, metaphore, amphora, diaphoresis, electrophoresis, semaphore, phosphorous, chromophore, oophorectomy, pheromone, tocopherol, paraphernalia, Christopher
φίλος philo- love, affinity philosophy, philanthropy, philology, bibliophile, anglophile, hemophilia, hydrophilic
φλεβός phlebo- vein phlebotomize, phlebotomy, phlebitis, thrombophlebitis, phlebolith, phlebogram
φλέγμα phlegm- flame, inflammation, burning phlegm, phlegmatic, phlegethon, phlegmon, phlogiston, phlox, flagrant, conflagration, flame, inflamed, flamboyant, flamenco, flamingo
φόβος phobia- fear, dread phobia, phobic, chromophobe, agoraphobia, claustrophobia, arachnophobia, xenophobic, homophobe, hydrophobic
φράγμα phragm- fence, hedge, partition phragmites, diaphragm, diaphragmatic
φρήν phreno- heart, soul, midriff phrenic, frenetic, frenzy, phrenology, gastrophrenic, costophrenic, schizophrenia
φῦκος phyco- algae, seaweed phycology, phycobilin, phycocyanin, phycomycetes, chlorophyceae
φῦλαξ phylaco- watch, guard, protect phylactery, phylacobiosis, anaphylaxis, cataphylaxis
φῦλή phylo- tribe phylum, phyletic, phylogeny, monophyletic, polyphyletic
φύλλον phyllo- leaf, foliage phyllotaxy, podophyllin, chlorophyll, epiphyllous
φύσις physi- birth, breath, nature physics, physical, physique, physiology, apophysis, diaphysis, epiphyseal, symphysis, hypophysis, emphysema, emphysematous
φυτόν phyto- plant, growth phytoplankton, gametophyte, zoophyte, epiphyte, tracheophyta, neophyte, osteophyte, dermatophytoses
φωνή phono- sound, voice phone, phoneme, phonics, phonation, phonetics, antiphonal, cacophony, symphony, euphonious, francophone, megaphone, telephone, anthem
φωτεινός photo- light, shining phosphorous, phosphate, phosphorescent, photograph, photosynthesis, photophore, photolysis, photogenic, telephoto

X χ chi

Pronounced like kye, the letter chi is used for the hard "ch" sound in Greek words such as chorus. The upper case Χ is sometimes used as a symbol for Christ (as in Xmas). In chemistry, Χ is also a symbol for the mole fraction. The chi-square test compares sample data with expected values to test hypotheses. The optic chiasm is the site where neurons from the eyes cross before entering the brain while chiasmata are the sites where chromosomes cross over; both resemble the letter X.

Root Stem Meaning Examples
χ chi- X-shaped, cross chiasm, chiasmata, suprachiasmatic, chi square
χαλκεία chalco- copper smith chalcolithic, chalcedony, chalcopyrite
χάος chao- empty space chaos, chaotic, gas, gaseous
χάραξ charax- engraving tool character, characteristic, characterize
χεῖλος cheilo- lip, edge, rim cheilosis, cheilitis
χείρ chiro- hand chiral, chiroptera, chiropractor, chiropodist, chiromancy, chirurgy, surgeon, enchiridion, telechiric
χηλή chela- claw, talon chelate, chelator, chelicera, cheliped, chela
χἶλιοι kilo- thousand chilopod, kilogram, kilometer, kilocalorie, kilowatt
χίμαιρα chimera- part goat, part lion chimera, chimeric, chimerism
χιτών chito- tunic chiton, chitin, chitinous
χλωρός chloro- yellow green chlorophyll, chloroplast, chlorine, chloride, perchlorate, hydrochloric, chloroform, chloroma, zoochlorella, chlorosis, chloremia, chloasma, achlorhydria
χόανος choano- crucible, funnel choanae, choanal, choanocyte, choanoflagellate, choanoderm, choanoid
χολή chole- bile, gall, wrath choler, cholera, choline, cholesterol, cholecystitis, cholecystokinin, cholangitis, cholangiogram, cholelithiasis, cholestasis, melancholy
χόνδρος chondro- grain, grist, cartilage chondrichthyes, chondrocranium, chondroblast, chondrosarcoma, hypochondriac, enchondroma, costochondral, achondroplasia, mitochondria, synchondrosis
χορδή chorda- string, gut cord, chord, chordate, chordoma, notochord, urochordate, hemichordate, harpsichord, clavichord
χορεύω chore- dancing chorea, choreography, chorus, choral, choir, terpsichore, hora
χρόνος chrono- time chronic, chronological, chronicle, chronobiology, chronograph, synchronize, anachronism
χρῦσός chryso- gold, golden chrysanthemum, chrysalis, chrysoberyl, chrysotile, chrysolite, chrysomelid
χρῶμα chromo- colored chrome, chromium, chromatin, chromatid, chromosome, chromaffin, chromophobe, chromatography, monochromatic, pheochromocytoma, achromatic, mercurochrome
χῦμός chyme- juice, poured in chyme, chyle, chemistry, chemotherapy, alchemy, mesenchyme, parenchyma, ecchymosis, humor, humidity
χωρίον chorio- container, membrane chorion, chorionic, choriocarcinoma, choroid, monochorionic

Ψ ψ psi

Pronounced like sigh, the letter psi is translated as two letters "ps" found in Greek words such as psychology. In medicine, psychiatry is sometimes abbreviated with the letter ψ. Psi is also the symbol for the planet Neptune because of its resemblance to the trident (fork) carried by the mythical god of the sea, which is perhaps why Ψ is also the symbol for water potential in cell biology.

Root Stem Meaning Examples
ψάμμος psammo- sand psammoma, psammomatous
ψεύδω pseudo- cheat, lie, false pseudopod, pseudonym, pseudoscience, pseudoephedrine, pseudocyst, pseudomembranous, pseudomonad
ψίττακος psittaco- parrot psittacosis, psittaciformes, psittacine
ψόα psoa- loin psoas, iliopsoas
ψῦχή psycho- soul, mind psyche, psychosis, psychology, psychiatry, psychedelic, psychometrics, psychotropic, psychopath, psychoanalysis

Ω ω omega

The Greek omega has a long "aw" sound (as in the English word "saw") and the name omega literally means mega or "large o." Upper case Ω is the symbol for electrical resistance, measured in ohms. Because omega is the last letter of the Greek alphabet, it is often used to represent the last in a series. A lower case ω indicates a position counted from the end of an organic molecule, as in omega-3 fatty acids that have a double bond in the third position from the end. The phrase alpha to omega suggests completeness, analogous to the expression "from A to Z." However in mathematics, the first uncountable number beyond infinity is represented with the symbol ω1.

Root Stem Meaning Examples
ὠδή ode- song ode, odeon, nickelodeon, epode, melody, parody, rhapsody, tragedy, comedy
ὠδἶν odyno- pain, suffering odynophagia, pleurodynia, glossodynia, anodyne
ὠλένη ole- elbow olecranon, ulna, ell
ὦμος omo-, -oma shoulder, tumor, swelling omohyoid, acromion, metacromion, humerus, lymphoma, hematoma, melanoma, glaucoma, edema, neuroma, carcinoma, carcinomatosis
ὠόν oo- egg oocyte, oogenesis, oogonium, oogamy, ootheca, oophorectomy, oophoritis
ὥρα horo- boundary, limit, season hour, horoscope, horizontal, horology
ὠτάριον oto- ear otic, otitis, otolaryngology, otalgia, parotid, otariidae
ὠχρός ochro- pale, yellow ochre, ochronosis
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