noun: (music) A vocal performance with no instrumental accompaniment.
adverb: (music) In a manner of a choir with no instrumental accompaniment; literally, "in the style of the (Sistine) Chapel (in Rome)", such as a musical Mass done a cappella.
adverb: (obsolete, music) In alla breve time.
adjective: (music) Singing solely or mainly without instrumental accompaniment.
adjective: (music, US) Related to a form of purely vocal music mostly associated with American college performance groups.
