English Words: O
15,494 words · Page 131 of 310
concave behind; applied especially to vertebrae in which the anterior end of the centrum is convex and the posterior concave
Any bird of the family Opisthocomidae, which comprises the hoazin and extinct relatives.
Of or pertaining to birds of the family Opisthocomidae, which is represented by the sole extant genus Opisthocomus and species Opisthocomus hoazin (hoazin).
Whose teeth include an enlarged pair at the back of the maxillae which normally angle backwards and are grooved to channel venom into the puncture.
Any early document (such as a roll of papyrus) that has writing on the back as well as the front.
A writing upon the back of anything, as upon the back of a sheet already written upon on one side.
Any of very many eukaryotes, including animals and fungi, whose flagellate cells (if any) propel themselves with a single posterior flagellum.
A stage in unicellular life-cycle, typically trypanosomes, where the flagellum is posterior of the nucleus, and passes through a groove in the cell body.
The posterior segment of the two-part body structure of chelicerates. Often used interchangeably with abdomen.
A plain or ornamented band of fabric, broad in the middle and narrow at the ends, and fastened in the front, used in Ancient Greece to support the hair behind the head.
Sustained tetanic spasm in which the body is bent backwards and stiffened, as produced by various diseases.
A rare genetic disorder affecting physical structures along the midline of the body.
A yellow-brown, addictive narcotic drug obtained from the dried juice of unripe pods of the opium poppy, Papaver somniferum, and containing alkaloids such as morphine, codeine, and papaverine.
A traditional Polish unleavened wafer baked from pure wheat flour and water, usually rectangular in shape and very thin, embossed with Christmas-related religious images.
An opportunistic lock on a file system object, used for caching purposes rather than to avoid modifications by multiple users at once.
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 131. 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.