O
Root Meaning in English Origin language Etymology (root origin) English examples ob-, o-, oc-, of-, og-, op-, os- against Latin obduracy, obdurate, obduration, obfuscate, oblique, obliquity, obstinate, obstreperous, occur, offend, omit, oppose, ostensible, ostentatious obel- spit, nail Greek (), () metobelus, obelisk, obelism, obelus obol- nail Greek () obol, obolus ocean- river, stream Greek () Oceania, oceanic ochl- crowd, mob Greek () enochlophobia, ochlocracy, ochlophobia oct- eight Greek (), (), () "eight times" hemi-octahedron, octad, octadic, octagon, octahedron, octameter, octode oct- eight Latin octangular, octennial, octovir octav- eighth Latin octaval octogen- eighty each Latin octogenarian, octogenary octogesim- eightieth Latin octogesimal octon- eight each Latin octonary ocul- eye Latin , ocular, oculus, ullage od- path, way Greek () anode, diode, odometer, parodos, pentode, tetrode, triode odi- hate Latin odious odont- tooth Greek () anodontia, conodont, cynodont, dicynodont, dysodontiasis, macrodontia, mastodon, odontoid, odontology, odontophore, orthodontics, orthodontist, pedodontics, periodontal, smilodon, Thrinaxodon, Zanclodon odor- fragrant Latin malodorous, odoriferous, odorous odyn- pain Greek () allodynia, anodyne, glossodynia, mastodynia, pleurodynia oec- house Greek (), () andromonecy, archdiocese, autoecious, autoecism, dioecious, dioecy, ecesis, ecologist, ecology, economics, economist, economize, economy, ecoregion, ecosystem, ecumenic, ecumenism, gynomonoecy, heteroecious, heteroecism, heteroecy, homoecious, monoecious, monoecy, oecology, oeconomus, oecumenic, oikology, oikophobia, palaeoecology, paleoecology, parish, paroecious, perioeci, trioecious oed-, ed- swell, swollen Greek (), (), () angioedema, edema, edematous, oedema, oedematous oen- wine Greek (), () enology, oenochoe, oenologist, oenology, oenophile, oenophilia, oinochoe oesophag- gullet Greek () oesophagectomy, oesophagitis, oesophagus oestr- gadfly, sting Greek (), , anestrous, anestrus, anoestrus, estrogen, estrogenic, estrus, oestrone, oestrus ogdo- eighth Greek (), () ogdoad -oid like Greek -οειδής (-oeidēs) asteroid, mucoid, organoid ole- oil Latin oleosity olecran- skull of elbow Latin from Greek () olecranon olig- few Greek () oligarchy, Oligocene, oligopoly, oligosaccharide, oligotrophic oliv- olive Latin olivaceous, olivary, olivette om- raw Greek (), () "rawness" omophagia, Omophagus om- shoulder Greek (), () acromion, omohyoid, omophorion -oma morbid growth, tumor Greek -ωμα melanoma omas- paunch Latin abomasum, omasum ombr- rain Greek () ombrogenous, ombrology, ombrometer, Ombrophila, ombrophilous, ombrophobe, ombrotrophic oment- fat skin Latin omental omin- creepy Latin , abominable, ominous ommat- eye Greek , () ommatidium, ommatophore omni- all Latin omnipotence, omnipresent, omniscient, omnivore omphal- navel Greek () omphalectomy, omphalic, omphalopagus, omphalophobia, paromphalocele on- ass Greek (), () Oniscidea, Oniscomorpha onc- barb, hook Greek , () Oncinocalyx, Oncorhynchus onc- (ΕΓΚ) bulk Greek , (), , oncocyte, oncocytoma, oncogenesis, oncologist, oncology oneir- dream Greek (), , () oneiric, oneirism, oneirocritic, Oneirocritica, Oneirodidae, oneirogen, oneirogenic, Oneiroi, oneiroid, oneirology, oneiromancy, oneironaut, oneironautics, oneirophobia, oneirophrenia, oneiroscopy oner- burden, load Latin , exonerate, exoneration, onerous, onus oni- price Greek (), () oniochalasia, oniomania, oniomaniac onomat- name Greek (), , () antonomasia, onomasiology, onomastic, onomasticon, onomastics, onomasty, onomatology, onomatophore, onomatopoeia ont- being, existence Greek (), () dysontogenesis, homoiousia, homoousia, monoousious, ontogenesis, ontogenetic, ontogeny, ontology, ousia, parousia onych- claw Greek (), (), , hapalonychia, Mesonychia, onychectomy, onycholysis, onychomancy, onychomycosis, onychophagia, onychophagy, onychorrhexis, onyx, paronychia, sardonyx onym- name Greek () acronym, allonym, anonymous, antonym, autonym, caconym, cryptonym, eponym, eponymous, eponymy, euonym, homonym, hyperonym, hyponym, hyponymy, meronym, meronymy, metonym, metonymy, metronymic, paronym, paronymous, pseudonym, pseudonymous, synonym, synonymous, synonymy, tautonym, tautonymous, tautonymy, troponym, troponymy, xenonym, xenonymy oo- egg Greek () bottarga, dioon, epoophoron, oidioid, oidium, ooblast, oocyst, oocyte, oocytogenesis, oogamete, oogamous, oogamy, oogenesis, oogonium, ooid, oolite, oolith, oology, oomancy, oophagy, oophorectomy, oophoron, ootheca, ootid, ootidogenesis, paroophoron op- hole Greek (), () metope, opaion opac- shady Latin opacity, opacus, opaque oper- work Latin , cooperate, inoperable, opera, operate, opus oper- cover Latin , interoperculum, kerchief, opercular, operculiform, operculum ophi- snake Greek () Brachyurophis, ophicephalous, Ophicephalus, Ophiceras, Ophiclinus, ophidiophobia, ophiolite, ophiologist, ophiology, ophiophagous, , ophiophagy, ophiophobia, Ophisaurus, Ophisops, ophitic ophthalm- eye Greek () exophthalmic, exophthalmos, microphthalmia, ophthalmia, ophthalmic, ophthalmologic, ophthalmologist, ophthalmology, ophthalmoparesis, ophthalmoplegia, parophthalmia, xerophthalmia opisth- behind Greek (), anopisthograph, opisthion, opisthobranch, opisthodomos, opisthoglyphous, opisthognathous, opisthograph, opisthokont, opisthosoma, opsimath, opsimathy ops-, opt- (ΟΠ) eye Greek (), (), (), () amblyopia, anopia, autopsy, biopsy, catadioptrics, catoptrics, catoptromancy, catoptrophobia, cyclops, diopter, dioptre, dioptrics, diplopia, eisoptrophobia, emmetropia, hemianopsia, myopia, opsoclonus, optic, optokinetic, panopticon, pleoptics, synopsis, synoptic, tritanopia opsi- late Greek (), opsimath opson- cook, prepare for eating Greek (), (opsōnia) opsonin, opsonoid opt- choose Latin adopt, adoptee, adoption, adoptive, co-option, coopt, cooptation, nonoptional, opt, optation, optative, option, optional, optionality optim- best Latin optimal, optimum or-, oro- mountain Greek (), Oread, orogenesis, orogenic, orogeny, orographic, orography, oronym or- mouth Latin (genitive ) "mouth" adosculation, inosculate, inosculation, interosculate, intraoral, oral, orifice, osculant, osculum, peroral ora- pray, plead Latin "to pray, plead" adore, adoration, exorable, inexorable, oracle, orate, oration, orator, oratorio, oratory, orison, perorate, peroration, perorator orb- circle Latin orbit orch- testicle Greek (), () anorchia, cryptorchidism, monorchism, orchid, orchiectomy, orchiopexy, Orchis, polyorchidism orches- dance Greek () orchestra ordin- order Latin , coordinal, coordinate, coordination, coordinator, disorder, extraordinaire, extraordinary, grandorder, incoordinate, incoordination, infraorder, inordinate, inordination, insubordinate, insubordination, magnorder, mirorder, ordain, ordainment, order, ordinal, ordinance, ordinand, ordinariate, ordinary, ordinate, ordination, ordinative, ordnance, ornery, parvorder, preordain, preorder, preordination, quasiorder, reordain, reorder, reordination, suborder, subordinary, subordinate, subordination, superordain, superorder, superordinate, superordination oreg- reach Greek (), (), (), (), () anorectic, anorexia, dysorexia, orectic, orexin, parorexia org- work Greek () orgasm organ- organ, instrument, tool Greek () organic, organism, organogenesis ori-, ort- rise Latin , aboriginal, abort, abortifacient, abortion, abortive, disorient, disorientation, orient, oriental, Orientalia, orientate, orientation, orientational, orientative, origin, original, originality, originate, origination, originator, reorient, reorientation orn- decorate Latin adorn, adornment, ornament, ornamental, ornamentation, ornate, ornative, ornature, suborn, subornation ornith- bird Greek () Avernus, ornithology, ornithomancy, ornithorhynchus, ornithosis orphan- Greek (), orphan orth- straight Greek (), orthocenter, orthocentric, orthodontia, orthodontic, orthodontist, orthodox, orthodoxy, orthographic, ortholog, orthologous, orthonym, orthopedic, orthoscope, orthosis, orthostat, orthostyle, orthotic oryz- rice Greek (), Oryza, Oryzomys, rice, risotto oscill- swing Latin oscillate, oscillation, oscillator, oscillatory osm- odor Greek (), anosmia, anosmic, cacosmia, coprosmia, dysosmia, dysosmic, euosmia, hyperosmia, hyperosmic, hyposmia, hyposmic, osmium, osmolagnia, osmophobia, osphresiolagnia, parosmia, phantosmia, troposmia osm- push, thrust Greek () osmometry, osmosis, osmostat, osmotic oss- bone Latin , exossation, interosseous, ossature, osselet, osseocartilaginous, osseointegration, osseous, ossicle, ossicular, ossiferous, ossification, ossifrage, ossify, ossuary oste- bone Greek (), () dysostosis, endosteum, exostosis, hyperostosis, monostotic, Osteichthyes, osteoarthritis, osteoblast, osteochondritis, osteochondrosis, osteoclast, osteogenic, osteogenesis, osteoid, osteology, osteolysis, osteoma, osteomalacia, osteonecrosis, osteopathy, osteopenia, osteoporosis, osteosarcoma, osteosis, osteothrombosis, osteotome, osteotomy, periosteum, synostosis osti- entrance Latin ostiary, ostiolar, ostiole, ostium ostrac- shell Greek (), (), () Entomostraca, Leptostraca, Malacostraca, ostracism, ostracize, ostracod, ostracoderm, ostracon, periostracum ostre- oyster Greek ostreophagist, oyster ot- ear Greek () anotia, Aotus, microtia, Myosotis, otalgia, otic, otitis, otocephaly, otocleisis, otoconium, otocyst, otodynia, otolith, otology, otopathy, otophyma, otoplasty, otorhinology, otorrhea, otosclerosis, otoscope, otoscopy, ototomy, parotic, parotid, periotic, synotia ov- egg Latin obovate, oval, ovarian, ovariole, ovary, ovate, ovicapsule, ovicidal, ovicide, oviduct, oviferous, oviform, oviposition, ovipositor, ovolo, ovular, ovulation, ovulatory, ovule, ovum, pluriovulate ovi- sheep Latin ovile, ovine oxy- sharp, pointed Greek () anoxia, anoxic, dioxide, hypoxia, monoxide, oxide, oxyanion, oxygen, oxyhalide, oxymoron, oxyntic, oxytone, paroxysm, pentoxide, polyoxide, tetraoxygen, tetroxide, trioxide oz- smell Greek (), (), ozocerite, ozone, ozopore References