Emily Dickinson Lexicon

AN'THEM, n. [Gr. αντι, against, and ὑμνος, a hymn, from ὑμνεω, to sing. See Hymn.]

A hymn sung in alternate parts; but in modern usage, a sacred tune or piece of music set to words, taken from the Psalms or other parts of the Scriptures, first introduced into church service in Elizabeth's reign. – Encyc.