English Words: O
15,494 words · Page 164 of 310
A tropical viral infection transmitted by biting midges and mosquitoes, causing fever, headache, muscle and joint pains, etc.
Relating to oral senses (e.g., taste, oral kinesthetic sense), and especially the innervation that provides for them.
A crystalline acid which was discovered in milk and is a growth factor for various microorganisms (as Lactobacillus bulgaricus) and an intermediate in pyrimidine biosynthesis; uracil-6-carboxylic acid, C₅H₄N₂O₄.
Of a voice: characterized by clarity, fullness, smoothness, and strength of sound; hence, of a person: having a clear, full, and strong voice, appropriate for public speaking, reading aloud, etc.
An existing acronym which has been redefined by some authority (such as a company legally defining its own name) as a nonacronymous name, severing its link to its previous meaning.
A medicinal drug which is effective in the treatment of some disease(s), but which is not manufactured or marketed because the demand is insufficient to cover the costs of supply.
An existing initialism which has been redefined as a nonacronymous name, severing its link to its previous meaning.
A notional machine representing a system or state of affairs that obviously facilitates suffering but is not acknowledged or examined, or for which no alternative is considered.
Spelling & Dictionary Insight
The English alphabetical index for the letter O contains 15,494 headwords drawn from our Wiktionary-derived dictionary table. At 50 entries per page the browse splits into 310 pages, and you are currently viewing page 164. 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.