Greek and Latin roots in English_O

Root Meaning in English Origin language Etymology (root origin) English examples
ob-, o-, oc-, of-, og-, op-, os- against Latin ob obduracy, obdurate, obduration, obfuscate, obstinate, obstreperous, occur, offend, omit, oppose, ostensible, ostentatious
oct- eight Greek ὀκτώ (oktō) octagon, octahedron, octode
oct- eight Latin octō octangular, octennial, octovir
octav- eighth Latin octāvus octaval
octogen- eighty each Latin octogeni octogenary
octogesim- eightieth Latin octogesimus octogesimal
octon- eight each Latin octoni octonary
ocul- eye Latin oculus, oculare ocular, oculus, ullage
od- path, way Greek ὁδός (hodos) anode, diode, odometer, pentode, tetrode, triode
odi- hate Latin odium odious
odont- tooth Greek ὀδούς, ὀδόντος (odous, odontos) odontology
odor- fragrant Latin odor odorous
oeco- house Greek οἶκος (oikos) ecology
oed- swollen Greek οἴδημα (oidēma) oedema
oen- wine Greek οἶνος (oinos) oenology
oesophag- gullet Greek οἰσοφάγος (oisophagos) oesophagus
offic- duty Latin officium office, officer, official, officiate, officious
ogdo- eighth Greek ὄγδοος (ogdoos) ogdoad
-oid like Greek -οειδής (-oeidēs) asteroid, mucoid, organoid
ole- oil Latin oleum oleosity
olecran- skull of elbow Latin from Greek ὠλέκρανον (ōlekranon) olecranon
olig- few Greek ὀλίγος (oligos) oligarchy, Oligocene, oligopoly, oligosaccharide, oligotrohic
oliv- olive Latin oliva olivaceous, olivary, olivette
-oma morbid growth, tumor Greek -ωμα melanoma
omas- paunch Latin omasum omasum
oment- fat skin Latin omentum omental
omin- creepy Latin omen, ominis abominable, ominous
omm- eye Greek ὄμμα (omma) ommatidium
omni- all Latin omnis omnipotence, omnipresent, omniscient, omnivore
omo- shoulder Greek ὦμος (omos) omohyoid
omphal- navel Greek ὀμφαλός (omphalos) omphalectomy
oner- burden Latin onus, oneris exonerate, onerous
onom- name Greek όνομα (onoma) onomatopoeia
ont- existing Greek ὄντος (ontos) ontogeny, ontology
-onym name Greek ὄνυμα (onuma) anonymous, antonym, pseudonym, synonym
oo- egg Greek ᾠόν (oion) oocyte
opac- shady Latin opacus opacity
oper- work Latin opus, operis cooperate, inoperable, opera, operate, opus
opercul- little cover Latin operculum operculum
ophi- snake Greek ὄφις (ophis) ophiophagy
ophthalm- eye Greek ὀφθαλμός (ophthalmos) ophthalmology
opisth- behind Greek ὄπισθεν (opisthen) opisthosoma, opsimath
opoter- either Greek ὁπότερος (hopoteros)
opt- eye Greek ὀπτός (optos) optical, panoptic
opt- choose Latin optare adopt, optional
optim- best Latin optimus optimum
or- mouth Latin os (genitive oris) "mouth" oral, orifice
ora- pray, plead Latin orare "to pray, plead" adore, adoration, inexorable, oracle, orate, oration, orator, oratory, orison
orb- circle Latin orbis orbit
orch- testicle Greek ὄρχις (orchis) orchid
ordin- order Latin ōrdō, ordinis ordinal, ordinary
organ- organ, instrument, tool Greek ὄργανον (organon) organism
ori-, ort- eastern Latin oriri, ortus orient
orn- decorate Latin ōrnāre adorn, ornament, ornate
ornith- bird Greek ὄρνις (ornis, ornithos) ornithology
orth- straight Greek ὀρθός (orthos) orthodontist, orthodox, orthodoxy, orthopedic, orthosis, unorthodox
oscill- swing Latin oscillum oscillation
oss- bone Latin os, ossis ossification
osteo- bone Greek ὀστοῦν (ostoun) osteoporosis
osti- entrance Latin ostium ostiole
ostrac- shell Greek ὄστρακον (ostrakon) ostracism, ostracoderm
ot- ear Greek οὖς, ωτός (ous, ōtos) otology
ov- egg Latin ovum oval, ovary, ovule
-over- close, cover Latin operire "to close, cover" cover, covert, coverture, discover, operculum
ovi- sheep Latin ovis ovine
oxy- sharp, pointed Greek ὀξύς (oxus) oxygen, oxymoron