English Words: O
1,431 words · Page 15 of 29
The design and operation of a system or process to make it as good as possible in some defined sense.
A person in a large business whose task is to maximize profits and make the business more efficient.
The best or most favorable condition, or the greatest amount or degree possible under specific sets of comparable circumstances.
The branch of physics that deals with the interaction of light with electronic devices, or the production of light from such devices
A person trained and skilled in examining and testing the eyes for defects, in order to prescribe corrective lenses or treatment.
A work of music or set of works with a specified rank in an ordering of a composer's complete published works.
Connects at least two alternative words, phrases, clauses, sentences, etc., each of which could make a passage true.
An evergreen tree of the genus Citrus such as Citrus sinensis which yields oranges (the fruit).
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 15. 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.