English Words: O
1,431 words · Page 29 of 29
A midland county of England bordered by Buckinghamshire, Gloucestershire, Berkshire, Wiltshire, Warwickshire and Northamptonshire.
Any of many enzymes which catalyze oxidation reactions, especially ones using molecular oxygen.
An addictive, semisynthetic opioid (trademark OxyContin) that is similar to morphine in effect and structure; C₁₈H₂₁NO₄.
The chemical element (symbol O) with an atomic number of 8 and relative atomic mass of 15.9994. It is a colorless and odorless gas. Sometimes called elemental oxygen to distinguish it from molecular oxygen.
A figure of speech in which two words or phrases with opposing meanings are used together intentionally for effect.
A hormone that stimulates contractions during labor, and then the production of milk; also plays a role in social bonding.
An exclamation typically expressing mild frustration or expressing feelings of uncertainty or concern.
Any of certain marine bivalve mollusks, especially those of the family Ostreidae (the true oysters), usually found adhering to rocks or other fixed objects in shallow water along the seacoasts, or in brackish water in the mouth of rivers.
An allotrope of oxygen (symbol O₃) having three atoms in the molecule instead of the usual two; it is a toxic gas, generated from oxygen by electrical discharge.
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 29. 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 31 of 31 entries carry a part-of-speech tag and 31 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.