One who adds to a common work. This house prefers participant where the person is the source rather than the helper.
Latin contribuere (to bring together, add), from com- (together) + tribuere (to allot, grant); one who adds to a work held in common rather than owned alone.
The Latin root allots rather than gives outright — a contributor's addition joins a pool it does not own alone. Where the person is the source of a work and not its assistant, this house reaches past the word to participant instead.