English Words: O
15,494 words · Page 298 of 310
One's own aircraft, as represented in a flight training simulation or traffic collision avoidance system.
Initialism of oral without: in prostitution, signifies performing oral sex without using a condom.
Initialism of Occupy Wall Street: a protest movement that began in 2011 in New York City's Wall Street financial district, primarily opposing social and economic inequality, greed, corruption and the influence of corporations on government.
A village in Owston and Newbold parish, Harborough district, Leicestershire, England (OS grid ref SK774079).
A village and civil parish in North Lincolnshire district, Lincolnshire, England (OS grid ref SE8000).
An orthorhombic-dipyramidal gray-white mineral containing antimony, bismuth, lead, silver, and sulfur.
A five-membered heterocycle having three carbon atoms, one oxygen atom, one boron atom and two double bonds; it, and its derivatives, are formally derived from an oxazole by replacing the nitrogen atom with one of boron
A narrow-spectrum beta-lactam antibiotic made by chemical modification of penicillin and administered in the form of its hydrated sodium salt C₁₉H₁₈N₃NaO₅S·H₂O to treat infections caused by penicillin-resistant staphylococci.
Any of several isomeric seven-membered, unsaturated heterocycles containing four carbon atoms, two nitrogen atoms, one oxygen atoms and three double bonds
A six-membered saturated heterocycle containing three carbon atoms, two nitrogen atoms and one oxygen atom; any derivative of this compound
An unsaturated six-membered heterocycle having three carbon atoms, one oxygen atom, two nitrogen atoms and two double bonds
Any five-membered heterocycle having two carbon atoms, two nitrogen atoms, one oxygen atom, and two double bonds
A complex nitrogenous substance, C₃N₃H₅O₃, obtained from alloxan (or when urea is fused with ethyl oxamate).
A poisonous nitrogenous base, C₆H₁₀N₂, obtained indirectly from oxamide as a thick clear oil with a strong odour and a physiological action resembling that of atropine.
A colourless, crystalline dicarboxylic acid, (COOH)₂, found in rhubarb, spinach and other plants, often as crystals of the calcium salt.
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 298. 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.