(1):

(n.) One who plays on a fiddle or violin.

(2):

(n.) A burrowing crab of the genus Gelasimus, of many species. The male has one claw very much enlarged, and often holds it in a position similar to that in which a musician holds a fiddle, hence the name; - called also calling crab, soldier crab, and fighting crab.

(3):

(n.) The common European sandpiper (Tringoides hypoleucus); - so called because it continually oscillates its body.