Ar"cha*ism (&?;), n. [Gr. 'archai:smo`s, fr. 'archai^os ancient, fr. 'archh` beginning: cf. F. archaïsme. See Arch, a.] 1. An ancient, antiquated, or old-fashioned, word, expression, or idiom; a word or form of speech no longer in common use.

2. Antiquity of style or use; obsoleteness.

A select vocabulary corresponding (in point of archaism and remoteness from ordinary use) to our Scriptural vocabulary.
De Quincey.