composition (often improvised) for a solo instrument (especially solo organ) and not a regular part of a religious service or musical performance
(military) a person who freely enlists for service
- military volunteer
controlled by individual volition
of your own free will or design
done by choice
not forced or compelled
"man is a voluntary agent"
"participation was voluntary"
"voluntary generosity in times of disaster"
"voluntary social workers"
"a voluntary confession"