someonecompletelyrandom

If you use it in the production of music. Anything that contributes to the piece that is being performed or the piece that is being recorded is an instrument, at least for that time. Whether I bang on my iPod with a stick for purcussion or I hit play and sounds come out of it. Anything can be used as an instrument. It's not a question of "Oh well that means my CAT is an instrument". Of course your cat is a cat. But if you recorded your cat with a piece or got him to meow with a piece, then he is being used as an instrument and therefor is an instrument/