Word origins

• -onymWord.
• -onymousHaving a specified number or type of names.
• -onymyUsed to form nouns describing the study, formation, or use of words or names.
• oomancyDivination through the use of eggs.
• oostegiteOne of the plates which, in some crustaceans, enclose a cavity in which the eggs are hatched.
• -opeEye
• ophid-Of or pertaining to snakes
• ophidiariumA place for keeping snakes.
• ophio-Of or pertaining to snakes
• ophiolatrysnake worship
• ophiothricidAny in the family Ophiotrichidae of brittle stars.
• ophiteAny of various rocks having snake-like markings, such as a mottled greenish porphyry.
• ophryonThe point in the brow just above the optic foramen, or eyesocket, and glabella.
• ophthalmo-Of or relating to eyes.
• opisometerA device for measuring the length of curved lines, such as on a map.
• opistho-in the back, behind, rear, posterior
• opisthognathidAny in the family Opistognathidae of jawfishes.
• opisthokontAny of very many eukaryotes, including animals and fungi, whose flagellate cells (if any) propel themselves with a single posterior flagellum.
• opodeldocA kind of plaster, said to have been invented by Mindererus, used for external injuries.
• opsiblasticExhibiting a period of dormancy before starting to develop.
• opsigamymarriage at an old age
• opsimathA person who learns late in life.
• -opsisSynonym of -opia (“seeing”).
• opsoclonusRapid, uncontrolled eye movement
• opsoninAny chemical produced by the body, including antibodies and complement proteins, that causes a pathogen to be more susceptible to phagocytosis.
• opto-optical
• -oramaUsed to form, from one noun, a second meaning "wide view of" the first, or (with ironic reference to the preceding sense) "surfeit of", "overattention to", or "exaggerated praise of" the first.
• orchesisThe act and/or art of dancing.
• orchesticRelating to dance
• orchialgiaPain in the testes.
• orchotomyThe surgical removal of a testicle; castration.
• orcosUse of an oath to enhance the believability of a statement.
• orecticOf or pertaining to desire or appetite
• oreinirostralHaving a tall, domed beak or snout.
• -orexiaRelated to appetite and eating disorders.
• orexigenicThat stimulates the appetite.
• ornitho-of or pertaining to birds
• ornithonAn aviary; a poultry house.
• oro-Of or pertaining to the mouth.
• oroideAn alloy of copper and zinc or tin that has a gold color, used in making inexpensive jewelry.
• orthianDenoting a type of singing at a very high pitch.
• orthocerasAny nautiloid cephalopod mollusc of the genus Orthoceras, known only as fossils
• orthoclasticHaving cleavage planes at right angles, as in orthoclase.
• OrthocorybantianSynonym of Massagetean.
• orthodoxiaCorrect praise; correct faith.
• orthoepyThe study of pronunciation.
• OrthogonianA member of the Orthogonian society, a social club at Whittier College founded by Richard M. Nixon in opposition to the wealthy elites at Whittier.
• orthogoniumright-angled triangle
• orthomorphicconformal
• orthopediaThe branch of medicine which deals with the prevention and correction of deformities in bodies; orthopedics.
• orthostatAn upright stone or slab, especially one which is part of a larger structure.
• orthotoneRetaining the accent independently; not enclitic; said of certain indefinite pronouns and adverbs when used interrogatively, which are enclitic in other situations.
• orthotonosmuscular rigidity associated with tetanus
• orthrosThe divine office or service at dawn.
• oryctographyThe description of fossils.
• osmazomeA substance formerly supposed to impart the characteristic meaty smell and taste to certain dishes.
• osmeteriumOne of a pair of scent organs in the larvae of certain swallowtail butterflies.
• -osmiaSmell; odour.
• osmicPertaining to, derived from, or containing, osmium; specifically, designating those compounds in which it has a higher valence.
• osmidrosisBody odour.
• osmo-osmosis
• osphresiolagniaSexual arousal through olfactory stimulation.
• OsroeneAn ancient Syriac kingdom, Roman province and historical region in northwestern Mesopotamia in modern Turkey and Syria, which enjoyed semi-autonomy to complete independence from the years of 132 B.C.E. to 244 C.E..
• osseoaponeuroticPertaining to an object composed of bone and aponeurosis; at the end of a muscle where it becomes tendon.
• osteo-bone
• osteoclasyThe surgical fracture and resetting of a bone.
• osteocollaA kind of glue obtained from bones.
• ostracodAny of many small crustaceans, of the class Ostracoda, that resemble a shrimp enclosed in a bivalve shell.
• ot-ear
• otacousticonAn instrument to aid hearing, such as an ear trumpet or hearing aid.
• otapostasisThe condition of abnormally protruding ears
• otarySynonym of eared seal.
• -oteHaving or equipped with a certain feature or structure.
• otheoscopeAn instrument for exhibiting the repulsive action produced by light or heat in a vacuum; a modification of the radiometer.
• otocinclusAny member of the species of small South American freshwater fish of the genus Otocinclus, popular in home aquariums.
• otocraneThe bony labyrinth.
• otopetrinAny of a group of transmembrane proteins associated with otoconia and with sensing the sour taste
• oxeaa monoaxial spicule which is pointed at both ends
• oxycrateA mixture of water and vinegar.
• oxynticProducing acid.
• oxytocicServing to promote uterine contractions, thus accelerating childbirth.
• ozadeneA defensive gland present in some arthropods, which secretes a foul-smelling substance to discourage predators.
• ozaenaAn atrophic type of chronic non-specific rhinitis characterized by a foul odor from the nose, now considered rare.
• ozænicOf or pertaining to ozænæ.
• ozoporeThe opening of a defensive gland present in some arthropods, which secretes a foul-smelling substance to discourage predators.
• pachnoliteA monoclinic-prismatic mineral containing aluminum, calcium, fluorine, hydrogen, oxygen, and sodium.
• pachy-Thick; thickness.
• pachysandraA genus, Pachysandra, of four or five species of evergreen shrubs or subshrubs, belonging to the boxwood family, Buxaceae, used ornamentally as groundcover.
• PædionThe Athenian plain.
• paedophagyThe act of feeding off larvae or eggs.
• paenismusA figure of speech consisting of a call for others to rejoice or exult over something, rather than merely stating the fact; an expression of feeling by calling on others to rejoice.
• pagophagiaThe pathological consumption of ice, a manifestation of pica, often resulting from iron or nutritional deficiencies.
• -pagusconjoined twins
• paki-Pakistan
• PalaeologusThe last dynasty ruling the Eastern Roman Empire.
• paleo-Old; ancient or primitive.
• paleocrysticOf, pertaining to, or derived from a former glacial formation; composed of ancient ice.
• paleologismA word or phrase that was coined in the distant past, often now obscured or offensive, or if recently used: possibly having a definition or implication different from that of any earlier usage.
• pali-recurrence, repetition
• palin-forms terms, of Greek origin, related to repetition or recurrence