Word origins

• nosocomephobiaAn abnormal fear of hospitals.
• nosognosiaThe ability of a person to recognize his or her own medical disorder.
• nosopoeticProducing disease.
• nostomaniaan overwhelming desire to return to familiar surroundings, or to one's home
• nostophobiaA fear of, or aversion to, returning to one's home.
• notaeumThe back (upper surface) of a bird.
• notariumA bone formed of fused vertebrae behind the shoulder of many species of birds and pterosaurs.
• notho-Used to form names of taxonomic ranks of hybrids
• notothyriumA triangular opening at the back edge of a brachiopod's brachial valve through which the pedicle may partially protrude.
• notoungulateAny of several extinct, hoofed, herbivorous mammals of the order †Notoungulata, from Cenozoic South America.
• noutheticBeing or relating to a form of Evangelical Protestant pastoral counseling based upon the Bible and focused on Christ.
• nyct-Night or darkness.
• nycti-Night.
• nyctitropicTurning or bending at night into different positions.
• nympho-nympha, nymphae (labia minora).
• nympholeptA person in a state of nympholepsy.
• obeliaAny of various colonial marine hydroids of the genus Obelia.
• obelionA craniometric point on the sagittal suture between the parietal foramina near the lambdoid suture.
• obelizeTo mark (a written or printed passage) with an obelus; to judge as spurious or doubtful.
• ochlagogueA manipulator of a mob who holds sway by use of inflammatory rhetoric, casting opprobrium, and by appeal to the lowest common denominator generally; an extreme and wholly unscrupulous demagogue; one who practises ochlagogy.
• ochlesisCrowd-poisoning; a disease occasioned or aggravated by overcrowding, especially due to lack of ventilation.
• ochlophobistA person with a phobia, or fear, of mob-like crowds, as opposed to simply open spaces like agoraphobia or large crowds as with enochlophobia.
• ocnophilA personality type characterised by avoidance of dangerous of unfamiliar situations, and the reliance on other people for security.
• octa-Eight.
• octachoronA four-dimensional object analogous to a cube, constructed out of eight cubes.
• octapodyA metre or verse of eight feet.
• octo-eight
• octodontidAny of the Octodontidae, a family of rodents including the common degu (Octodon degus) and 12 other South American species
• -odeWay, path, travel.
• odmylA volatile liquid, said to have an unpleasant garlicky odour, obtained by boiling sulfur with linseed oil.
• odo-Relating to roads.
• odologyThe study of roads or paths.
• odontalgiatoothache
• -odontiabranch of dentistry
• odonto-tooth
• odontogenyThe generation, or mode of development, of the teeth.
• odontoidResembling a tooth, especially in shape
• odonymAn identifying name given to a street; a street name.
• odyleSynonym of od (“a hypothetical force or natural power, now proved not to exist, which was supposed by Carl Reichenbach and others to inhere in certain people and produce phenomena such as animal magnetism and mesmerism, and to be developed by various agencies, as by chemical or vital action, heat, light, magnets, etc.”).
• odynometerSynonym of algometer.
• odynophagiaSevere pain in the mouth or esophagus when attempting to swallow.
• odynophobiaA pathological fear of pain.
• œnolinColouring matter of any grapes and red wines.
• oenomancydivination by studying wine
• oenopoeticOf or pertaining to winemaking; vinicultural.
• ogdo-Synonym of octo-.
• ogdoadA thing made up of eight parts.
• ogdohedralHaving hemimorphic trigonal pyramidal symmetry
• oikeiosisThe perception of something as being one's own, or belonging to oneself.
• oikocrystAn enclosing crystal in a poikilitic fabric.
• oikologyThe science of houses and homes, considered especially in respect of their sanitary conditions.
• oikonymA type of toponym denoting a settlement or its part.
• oikophobeOne who suffers from oikophobia, especially one who identifies with a global group rather than feelings of patriotism or chauvinism.
• oikophobiaEcophobia; fear of a home environment.
• oikophobicExhibiting or characterized by oikophobia, a dislike of one's own culture or compatriots.
• oligo-few, several
• oligodipsiaPathologically reduced or absent sense of thirst.
• oligolecticRelating to, or characteristic of, oligolecty.
• oligolectyThe preference of an insect pollinator (chiefly a bee) for pollinating only a few plant species.
• oligopsonyAn economic condition in which a small number of buyers exert control over the market price of a commodity.
• olisbosA dildo.
• olistolithAny of a mass of blocks of rock or mud that make up an olistostrome.
• olistostromeA sedimentary deposit composed of a chaotic mass of heterogeneous material, such as blocks and mud, known as olistoliths, that accumulates as a semifluid body by submarine gravity sliding or slumping of the unconsolidated sediments.
• -omaForming nouns indicating disease or morbidity.
• omalgiapain in the shoulder
• ombrophyteAny plant that is adapted to rainy conditions or habitats
• ommatidiumOne of the conical substructures which make up the eyes of invertebrates with compound eyes.
• ommatophoreAn eyestalk.
• omodyniapain in the shoulder
• omostegiteThe part of the carapace of a crustacean situated behind the cervical groove.
• omphacineMade from unripe olives.
• omphaciteAny of a range of green, monoclinic pyroxene minerals found in eclogites and similar rocks; they are solid solutions of jadeite and diopside.
• omphalo-Relating to the navel.
• omphaloidShaped like a navel.
• omphalomesaraicSynonym of omphalomesenteric.
• omphalosAn ancient religious stone artifact, or baetylus, used to denote the direction of the "center" of the world.
• Omphalos hypothesisThe proposition that God created the universe within the past few thousands of years but also introduced false evidence that the universe is of great age.
• omphaloskepsisThe contemplation of or meditation upon one's navel; navel-gazing.
• omphaloskepticOne who contemplates or meditates upon one's navel; one who engages in omphaloscopy.
• -oncusUsed to form names of conditions involving a tumor, swelling, or mass.
• oneiricOf or pertaining to dreams.
• oneiro-dream
• oneirocrisyPrognostication based on the interpretation of dreams.
• oneirocriticAn interpreter of dreams.
• oneirocriticalOf or relating to the interpretation of dreams.
• OneiroiThe gods and personifications of dreams; the sons of Hypnos and Pasithea, or Nyx and Erebus.
• oneiroidCharacterized by a dream-like or nightmare-like state, often as part of schizophrenia.
• oniochalasiaThe act of purchasing objects as a form of mental relaxation.
• oniomaniaAn abnormal impulse to buy things, or a condition characterised by such impulses.
• onomancydivination by the letters of a name; nomancy
• onomasticonA book, list, or vocabulary of names, especially of people.
• onomato-name
• onomatopoesyThe use of onomatopoeia.
• onomatopoieticAn onomatopoietic word.
• onotherapyDonkey riding as physical therapy.
• -ontIndicating a life-form or life-stage, especially with regards to reproduction.
• OntosA light, armored anti-tank vehicle of a particular kind.
• onychocryptosisingrown toenail
• onychomadesisPeriodic idiopathic shedding of the nails beginning at their proximal ends, possibly caused by the temporary arrest of the function of the nail matrix.
• onychotillomaniaA compulsion for picking and tearing at one's fingernails or toenails.