A vocal performance with no instrumental accompaniment.
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.
Singing solely or mainly without instrumental accompaniment.
Related to a form of purely vocal music mostly associated with American college performance groups.
A composition written or performed without lyrics, sometimes using a lead instrument to replace vocals.
The instrumental case.
Pertaining to, made by, or prepared for an instrument, especially a musical instrument (rather than the human voice).
Applied to a case expressing means or agency, generally indicated in English by by or with with the objective.
Serving as an instrument, medium, means, or agency.
essential or central; of great importance or relevance.