Word origins

• ordinativeTending to ordain; directing; giving orders.
• ordo amorisThe method in which love for others is prioritized, with those most closely related and in close proximity getting priority.
• OrdovicesAn ancient tribe of Britannia, situated opposite the island of Anglesey.
• oreophilousMountain-loving; tending to inhabit mountains.
• ore rotundoSpoken in an eloquent, clear, and confident manner.
• OrestheusSon of Lycaon
• OrestisAn ancient district of Macedonia, in modern Greece
• orexisThe affective and conative character of mental activity as contrasted with its cognitive aspect; the appetitive aspect of an act; desire, appetite.
• organificMaking an organic or organized structure; producing an organism.
• organum triplumA type of organum with three voices, pioneered by medieval composer Pérotin.
• orichalcumA valuable yellow metal known to the Ancient Greeks and Romans; now sometimes interpreted as referring to a natural alloy of gold and copper, and sometimes treated as a mythical substance.
• original justiceThe state of Adam and Eve before they sinned.
• original sinAdam's disobedience to God, beginning with his eating of the forbidden fruit, often depicted as an apple.
• -oriumForming nouns denoting a place for a particular function or thing.
• ornativeA noun case that means "endowed with" or "supplied with".
• ornatrixA tirewoman, an adorner.
• ornatureDecoration; ornamentation.
• ornifyTo ornament.
• oro-Of or pertaining to the mouth.
• Orodesany of several rulers of Parthian Empire and kings of its nearby kingdoms including Elymais, Armenia, and Hatra
• orphanityThe state of being an orphan; orphanhood.
• orphanotrophiumA kind of orphanage in ancient times.
• orphanotrophyA hospital for orphans.
• ortetThe original single parent plant from which a clone ultimately derives.
• ortiveOf or relating to the time or act of rising; eastern.
• -oryAdded to nouns and verbs (often Latinate) to form adjectives meaning “of”, “pertaining to”, or “serving for”.
• oryctognosyKnowledge about things dug up, especially what is now considered mineralogy.
• oryzalinA selective herbicide used to control annual grasses etc. in food crops
• oryzastrobinA particular strobilurin fungicide.
• oryzivorousHaving a diet rich in rice.
• -os-a monoclonal antibody that targets bone
• os-Against; facing; a combining prefix found in verbs of Latin origin.
• OscanOf or pertaining to the Oscan language or Oscan people, or their writing system.
• oscineOf or pertaining to songbirds (suborder Passeri).
• oscinineOf or pertaining to the Oscines, or songbirds (birds of the clade Passeri).
• oscitantyawning or gaping
• oscitateTo gape or yawn.
• oscitationThe act of yawning or gaping.
• os clitoridisThe baubellum.
• os cordisOssified cardiac cartilagenous tissue, typically parts of the cardiac skeleton.
• os coxaeSynonym of hip bone.
• osculantAdhering closely; applied to certain creeping animals, such as caterpillars.
• osculateTo kiss.
• osculationThe action of kissing.
• osculatoryA religious tablet, usually carrying a representation of Christ or the Virgin Mary, which is kissed by the priest during the Mass ("kiss of peace"); it is then passed to others at the mass who also kiss it.
• osculumOne of the suckers on the head of a tapeworm.
• -oseFull of; affected by.
• OsiandrianOf or relating to Andreas Osiander (1498–1552), German Lutheran theologian.
• os penisThe baculum.
• ossariumAn ossuary.
• ossicleA small bone (or bony structure), especially one of the three of the middle ear.
• ossiculumAn ossicle.
• ossiferousContaining or yielding bone.
• ossificCapable of producing bone; having the power to change cartilage or other tissue into bone.
• ossilegiumThe collection of the bones of a dead person, after decomposition of the soft tissue, for placement in an ossuary
• ossuariumA charnel house; an ossuary.
• ostentTo make an ambitious display of; to exhibit or show boastingly; to ostentate.
• ostentateTo make an ambitious display of; to exhibit or show boastingly.
• ostentatora boaster, ostentatious person
• ostentatrixAn ostentatious woman
• ostiariusAn ostiary; a doorman; a porter.
• ostiaryThe mouth of a river; an estuary.
• ostioleA small hole or opening through which certain fungi release their mature spores.
• ostraceanAny bivalve of the family Ostreidae; an oyster.
• ostreaceousOf or pertaining to an oyster, or to a shell.
• ostreaphileAn lover or aficionado of oysters as food.
• otalgiaearache
• otiantAt ease, at leisure; idling, indolent.
• otioseHaving no effect.
• Otrerathe creator and first Queen of the Amazons
• otrovertA person who is unable to feel a connection to social groups or collectives, as distinct from both an introvert and an extrovert.
• ottomyA skeleton.
• Our Lady of SorrowsSynonym of Mary, mother of Jesus, in particular reference to her grief at the Christ's crucifixion.
• ovantexultant
• ovariousPertaining to or made up of eggs.
• over the transomOf a work submitted for publication, unsolicited.
• ovi-Egg.
• ovicularOf, resembling, or pertaining to an egg.
• OvidianOf or pertaining to the Latin poet Ovid; resembling the style of Ovid.
• ovigerA leg, of some pycnogonids, that is modified to carry eggs
• oviraptorAny of several bipedal dinosaurs, of the genus Oviraptor, from the late Cretaceous period.
• oviscapeThe basal part of the ovipositor of some species of insects, typically the non-retractile sheath that remains exposed when the ovipositor is withdrawn and not in action.
• ovismThe belief that the ovum holds all material needed for the development of the embryo.
• ovistSomeone who believes that the complete embryo is contained preformed within the ovum; a proponent of ovism.
• ovo-egg; ovum
• ovoviviparousOf or pertaining to such kind of animals such as some reptiles whose eggs hatch inside their body.
• oxygalSour milk.
• pabulationThe act of eating or feeding.
• pabulousnourishing
• pacableAble to be easily pacified.
• pacatepeaceful, tranquil
• pacatedpacified, placated
• pacationpacifying, placation
• pacificateSynonym of pacify.
• pacificatorA peacemaker, a pacifier.
• pacificatoryPromoting peace; conciliatory.
• pactitiousSettled by a pact or treaty; relating to pacts or treaties.
• pactum illicitumAn unlawful agreement.
• paenulaA kind of woollen cloak or mantle used by Romans, worn on journeys and in rainy weather.
• paenultima lawThe rule of Classical Latin pronunciation which states that a word receives antepenultimate stress if its penult is a short or metrically light syllable, but receives penultimate stress if its penult is a long or metrically heavy syllable.