oxide

Webster's Dictionary (1913)

Origin: F. oxygène oxygen + acide acid: cf. F. oxyde. The French word was correctly spelt oxide, till about the year 1840, when, in ignorance or forgetfulness of the true history and composition of the word, the orthography was change to make it represent the υ of Gr. ὀξύς, from which it was supposed to be directly derived.

Chemistry A binary compound of oxygen with an atom or radical, or a compound which is regarded as binary; as, iron oxide, ethyl oxide, nitrogen oxide, etc.

☞ In the chemical nomenclature adopted by Guyton de Morveau, Lavoisier, and their associates, the term oxides was made to include all compounds of oxygen which had no acid (F. acide) properties, as contrasted with the acids, all of which were at that time supposed to contain oxygen. The orthography oxyde, oxyd, etc., was afterwards introduced in ignorance or disregard of the true etymology, but these forms are now obsolete in English. The spelling oxid is not common.

Webster’s Revised Unabridged Dictionary (1913), from GCIDE 0.54