voluntary -- (composition (often improvised) for a solo instrument (especially solo organ) and not a regular part of a religious service or musical performance)
Overview of adj voluntary
The adj voluntary has 2 senses
voluntary -- (of your own free will or design; done by choice; not forced or compelled; "man is a voluntary agent"; "participation was voluntary"; "voluntary manslaughter"; "voluntary generosity in times of disaster"; "voluntary social workers"; "a voluntary confession")
voluntary -- (controlled by individual volition; "voluntary motions"; "voluntary muscles")
(Sound)
