English Words: O

1,431 words · Page 11 of 29

Omanname

A country in West Asia in the Middle East. Official name: Sultanate of Oman. Capital: Muscat.

Omaninoun

A person from Oman or of Omani descent.

Omarname

Omar bin al-Khattab, second Sunni Islamic caliph and a companion of Muhammad

Omariname

A male given name from Arabic.

OMBname

Initialism of Office of Management and Budget.

ombrenoun

A Spanish card game, usually played by three people. It involves forty cards, omitting the ranks of 8, 9 and 10.

ombudsmannoun

An appointed official whose duty is to investigate complaints, generally on behalf of individuals such as consumers or taxpayers, against institutions such as companies and government departments.

OMCnoun

Initialism of original male character.

omeganoun

The twenty-fourth letter of the Classical and the Modern Greek alphabet, and the twenty-eighth letter of the Old and the Ancient Greek alphabet, i.e. the last letter of every Greek alphabet. Uppercase version: Ω; lowercase: ω.

omelettenoun

A dish made with beaten eggs cooked in a frying pan without stirring, flipped over to cook on both sides, and sometimes filled or topped with other foodstuffs, for example cheese or chives.

omennoun

Something which portends or is perceived to portend either a good or evil event or circumstance in the future, or which causes a foreboding; a portent or augury.

omeprazolenoun

A substituted benzimidazole (trademark Losec, Prilosec) which is a proton pump inhibitor and inhibits secretion of gastric acid, being given orally in the treatment of ulcers and gastroesophageal reflux; 5-methoxy-2-(4-methoxy-3,5-dimethyl-2-pyridylmethylsulfinyl)benzimidazole, C₁₇H₁₉N₃O₃S.

omernoun

A former small Hebrew unit of dry volume equal to about 2.3 L or 2.1 quarts.

OMFGintj

Initialism of oh my fucking God.

OMGintj

An exclamation of excitement, surprise, shock etc.; oh my God

ominoun

A man.

omicronnoun

The 15th letter of the Classical and Modern Greek alphabets (16th in Ancient and Old Greek), used in ordering lists as in naming (astronomy) the 15th star of a constellation or (epidemiology) the 15th discovered major variant of a disease.

Omidname

A transliteration of the Persian male given name امید (omid).

ominousadj

Of or pertaining to an omen or to omens; being or exhibiting an omen; significant.

ominouslyadv

In an ominous manner; with sinister foreboding.

omissionnoun

The act of omitting.

omitverb

To leave out or exclude.

omittedverb

simple past and past participle of omit

omittingnoun

An act of omission.

omnibusnoun

A bus (vehicle for transporting large numbers of people along roads).

omnichanneladj

Integrating all physical (offline) and digital contact channels to provide a unified customer experience.

omnidirectionaladj

In every direction, especially of a radio system capable of transmitting or receiving signals in all directions, or of a microphone capable of detecting sound from all directions.

omnipotencenoun

Unlimited power; commonly attributed to a deity or deities.

omnipotentadj

Having unlimited power, force or authority.

omnipresencenoun

The ability to be, or the characteristic of being, at all places at the same time (usually only attributed to God).

omnipresentadj

Being everywhere simultaneously.

omnisciencenoun

The capacity to know everything.

omniscientadj

Having total knowledge.

omniumnoun

A multiple race event in track cycling. Historically the omnium has had a variety of formats. Currently it consists of the following six events: flying lap, points race, elimination, individual pursuit, scratch race, and time trial.

omnivorenoun

An animal which is able to consume both plants (like a herbivore) and meat (like a carnivore).

omnivorousadj

Having a diet which is neither exclusively carnivorous nor exclusively herbivorous.

OMSnoun

Initialism of orbital manoeuvering system: NASA terminology for orbital maneuvering rockets.

Omskname

A city, the administrative center of Omsk Oblast, Russia, the seventh-largest in the country by population.

onadj

In the state of being active, functioning or operating.

on'tcontraction

Contraction of on + it.

Onaname

A surname from Spanish.

Onamname

A harvest festival celebrated in Kerala, India.

onboardadj

Carried or used on or in a vehicle or vessel.

onboardingnoun

(business) The process of bringing a new employee on board, incorporating training and orientation.

onceadv

One and only one time.

oncogenenoun

Any gene that contributes to the conversion of a normal cell into a cancerous cell when mutated or expressed at high levels.

oncogenicadj

Causing the formation of tumors.

oncologistnoun

A doctor or scientist who specializes in oncology.

oncologynoun

The branch of medicine concerned with tumors, including study of their development, diagnosis, treatment, and prevention.

oncomingnoun

Approach, onset

Spelling & Dictionary Insight

The English alphabetical index for the letter O contains 1,431 headwords drawn from our Wiktionary-derived dictionary table. At 50 entries per page the browse splits into 29 pages, and you are currently viewing page 11. Every row above is a dictionary-backed entry with a canonical slug, and each links through to a full definition page with pronunciation, senses, etymology, and related-word data where available.

On this page 50 of 50 entries carry a part-of-speech tag and 50 carry at least one stored definition. Coverage varies across letters because Wiktionary volunteers build entries at different speeds for different parts of the alphabet, letters with common starting sounds (S, C, T, P) usually have the densest coverage, while less frequent starters (X, Q, Z) tend to have shorter but more specialised lists. PlainSpell surfaces whatever data is present and links back to the source when a definition is not yet recorded.

For readers using this index as a spelling reference, the guarantee is that every form you see on the list is a documented English headword, not a guess, not a derived inflection lacking a lemma row. If a word you expected to find is absent from the "O" list, it usually means the form exists only as an inflection of another lemma (e.g. a past participle stored under the infinitive) or the entry has not yet been imported from Wiktionary. Use the search bar or the misspelling lookup to resolve these cases.