Singing solely or mainly without instrumental accompaniment.
Related to a form of purely vocal music mostly associated with American college performance groups.
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.
A vocal performance with no instrumental accompaniment.
Naturally producing or produced by an instrument without electrical amplification or the need thereof.
Utilizing sound energy in its operation.
(of building materials) Used for soundproofing or modifying sound.
(of an explosive mine or other weapon) Able to be set off by sound waves.
The properties or qualities of a room or building that determine how sound is transmitted in it.
A medicine or other agent to assist hearing.