English Words: O
15,494 words · Page 33 of 310
Any of the Octodontidae, a family of rodents including the common degu (Octodon degus) and 12 other South American species
A liturgical book containing a repertoire of hymns ordered in eight parts according to the eight echoi (tones or modes), used in many rites of Eastern Christianity.
Pertaining to, derived from, or resembling octane; used mostly to designate any of a group of acids including caprylic acid.
Being a form of gear or tooth that resembles the involute, but whose complete path of contact on the surface of a sphere is in the form of a figure eight.
An 8-dimensional nonassociative extension of a quaternion with a real part and 7 imaginary parts (each a real multiple of a distinct square root of −1).
An aromatic amine, 4-(2-amino-1-hydroxy-ethyl)phenol, related to noradrenaline, having similar characteristics to dopamine.
A modern stringed instrument intended to be able to play the tone combinations of the tenor guitar, tenor banjo, ukulele, taro-patch fiddle, tiple, mandolin, mandola and mandocello.
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 33. 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.