oxymoron.noun,.plural.oxymora or oxymorons
a rhetorical figure in which incongruous or contradictory terms are combined, as in 'a deafening silence' and 'a mournful optimist', and 'microsoft works'
oxymoronic.adjective
oxymoronically.adverb

obligate, obligated, obligating, obligates.transitive verbs
to bind, compel, or constrain by a social, legal, or moral tie; to cause to be grateful or indebted; oblige; to commit (money, for example) in order to fulfill an obligation
obligable.adjective
obligately.adverb
obligator.noun
synonym.force
obligation.noun
the constraining power of a promise, contract, law, or sense of duty; the act of binding oneself by a social, legal, or moral tie; a social, legal, or moral requirement, such as a duty, contract, or promise that compels one to follow or avoid a particular course of action; a course of action imposed by society, law, or conscience by which one is bound or restricted; something owed as payment or in return for a special service or favor; the service or favor for which one is indebted to another; the state, fact, or feeling of being indebted to another for a special service or favor received
obligational.adjective
synonyms.responsibility, duty
obligatory.adjective
morally or legally constraining; binding; imposing or recording an obligation; of the nature of an obligation; compulsory (attendance is obligatory) 
obligatorily.adverb

obliging.adjective
ready to do favors for others; accommodating; amiable
obligingly.adverb
obligingness.noun
oblige, obliged, obliging, obliges.verbs
transitive verb use.to constrain by physical, legal, social, or moral means; to make indebted or grateful (I am obliged to you for your gracious hospitality); to do a service or favor for: (they obliged us by arriving early)
intransitive verb use.to do a service or favor (he soloist obliged with yet another encore)
obliger.noun

Orion.noun
a constellation in the celestial equator near Gemini and Taurus, containing the stars Betelgeuse and Rigel

Ockham.noun
"The English Scholastic William of Ockham formulated the most radically nominalistic criticism of the Scholastic belief in intangible, invisible things such as forms, essences, and universals. He maintained that such abstract entities are merely references of words to other words rather than to actual things. His famous rule, known as Ockham's razor, which said that one should not assume the existence of more things than are logically necessary, became a fundamental principle of modern science and philosophy.".Microsoft® Encarta® Encyclopedia 99.
Ockham's razor.also.Occam's razor.noun
also called.law of parsimony
a rule in science and philosophy stating that entities should not be multiplied needlessly, and interpreted as meaning that the simplest of two or more competing theories is preferable and that an explanation for unknown phenomena should first be attempted in terms of what is already known

ovary.noun
botany – the ovule bearing lower part of a pistil that ripens into a fruit

ovule.noun
a minute structure in seed plants, containing the embryo sac and surrounded by the nucellus, that develops into a seed after fertilization
ovular or ovulary.adjective

octahedral.adjective
having eight plane surfaces
octahedrally.adverb

oath.noun,.plural-oaths
open acknowledgment before God of one's commitment to perform something which carries with it the weight of God's presence, and so, the thing to be performed is thus of sincerity a thing of higher consciousness; a solemn, formal declaration or promise to fulfil a pledge, often calling on God or a sacred object as witness; something declared or promised

ordinance.noun
a command or order coming from an authorized body, such as an Order in Council; a custom or practice established by long usage; a statute or regulation, especially one enacted by a city government

omit, omitted, omitting, omits.transitive verbs
to fail to include or mention; leave out (omit a word)

omission.noun
the act or an instance of omitting; the state of having been omitted; something omitted or neglected

obtrude, obtruded, obtruding, obtrudes.verbs
transitive verb senses.to impose.(oneself or one's ideas) on others with undue insistence or without invitation; intrude; to thrust out; push forward; to push forward into consideration or sight
intransitive verb senses-to impose oneself on others
obtruder, obtrusion.nouns

often, oftener, oftenest.adverbs
many times; frequently

oft.adverb
often

oftentimes.noun, also.ofttimes.adverb
frequently; repeatedly

oodles.plural noun
a great amount or number (oodles of fun)

obsessive.adjective
of, relating to, characteristic of, or causing an obsession-(obsessive gambling); excessive in degree or nature (an obsessive need to win)
obsessive, obsessiveness.nouns
obsessively.adverb
obsess, obsessed, obsessing, obsesses
transitive use.to preoccupy the mind of excessively
intransitive use.to have the mind excessively preoccupied with a single emotion or topic
obsessor.noun

occult.adjective
of, relating to, or dealing with supernatural influences, agencies, or phenomena; hidden; mysterious
occult, occulted, occulting, occults.verbs
transitive senses.to conceal or cause to disappear from view
intransitive senses.to become concealed or extinguished at regular intervals (a lighthouse beacon that occults every 45 seconds)
occultly.adverb
occultness.noun

ornate.adjective
elaborately, heavily, and often excessively ornamented; flashy, showy, or florid in style or manner; flowery
ornately.adverb
ornateness.noun

onset.noun
the beginning of something (the seemingly onset of totalitarianism (note - onset is usually followed by of, examples - the onset of winter, the onset of the disease/war)

omnipotent.adjective
having unlimited or universal power, authority, or force; all powerful; infinite
omnipotent.noun
one having unlimited power or authority (the Infinite One)
omnipotence.or.omnipotency.noun
omnipotently.adverb

ordinary.adjective
commonly encountered; usual; common; of no exceptional quality; average
ordinary.noun;.plural.ordinaries
the usual or normal condition or course of events (nothing out of the ordinary occurred)
ordinariness.noun
Law - a judge or other official with immediate rather than delegated jurisdiction