English Words: O
15,494 words · Page 306 of 310
A monoclinic mineral containing aluminium, barium, magnesium, oxygen, silicon and titanium.
A substance, containing sodium peroxide and other salts, which releases oxygen upon contact with water.
A mixture of honey, water, and vinegar, boiled to a syrup, sometimes mixed with herbs or spices.
An addition reaction in which the elements of water are added across an alkene's double bond to form an alcohol; the reaction proceeds via the addition of mercuric acetate, the mercuric group being removed by reduction
A sympathomimetic drug with vasoconstrictive activity that is used in the form of its hydrochloride C₁₆H₂₄N₂O·HCl chiefly as a topical nasal decongestant, developed from xylometazoline.
A synthetic anabolic steroid developed in 1960, used to treat osteoporosis and anaemia and to stimulate muscle growth in undernourished or underdeveloped patients.
A figure of speech in which two words or phrases with opposing meanings are used together intentionally for effect.
The substance resulting from exposure of myoglobin to oxygen, responsible for the red colour of meat.
Any derivative of a neolignane in which the two propylbenzene residues are joined indirectly by an oxygen atom
Any of several inorganic compounds of the general formula Mₓ(ON)_y, some of which are inorganic polymers
Any addition reaction in which an oxygen atom and a palladium atom are added across a double bond or triple bond (normally to form a reactive intermediate)
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 306. 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.