English Words: O
15,494 words · Page 167 of 310
An orthorhombic mineral containing aluminum, hydrogen, iron, magnesium, oxygen, and silicon.
The active ingredient in most tear gas, C₁₀H₅ClN₂, also called CS gas
Being uniformly sensitive across the entire visible range, and thus reproducing colours faithfully
Describing an erythroblast, derived from a polychromatophilic one, that is approaching the colour of a mature erythrocyte
Any of a group of mixed oxides of chromium and another metal (typically a rare earth element) of general formula MCrO₃
Describing any Lorentz transformation or Galilean transformation which preserves the direction of time
Potassium aluminum silicate, KAlSi₃O₈, a common feldspar of igneous, plutonic, and metamorphic rocks. Orthoclase is the main feldspar of pegmatite occurrences, where it is most commonly flesh-colored. Orthoclase is used in the ceramic and glass industries and as a decorative gravel.
An element of an ortholattice which is the result of applying an orthocomplementation function to a given element (of that ortholattice) (of which it is said to be the orthocomplement).
An involution on a complemented lattice which is order-reversing and maps each element to a complement.
Having or being a (mollusc) shell which is conical and straight (not curved or spiraled).
Any of two or more cousins who are the children of siblings of identical gender, i.e. children of brothers or of sisters.
A cumulate rock in which the groundmass is of different composition to the accumulated crystals.
Constraints or assessments applied to transactional or warehoused data to assure data quality.
An instrument used to determine the true contour and dimensions of any internal organ or other object rendered visible by X-rays, the latter being deflected so as to be made parallel.
Conforming to the accepted, established, or traditional doctrines of a given faith, religion, or ideology.
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 167. 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.