any small, burrowing crab of the genus Uca, characterized by one greatly enlarged claw in the male.
Origin
1700-10, Americanism
Examples from the web for fiddler crab
The park supports a wide variety of marine life, including shrimp and fiddler crab.
The fiddler crab's shell is squarish, males have one large claw.
The fiddler crab breathes air and lives in a burrow in the mud.
British Dictionary definitions for fiddler crab
fiddler crab
noun
1.
any of various burrowing crabs of the genus Uca of American coastal regions, the males of which have one of their anterior pincer-like claws very much enlarged
Word Origin
C19: referring to the rapid fiddling movement of the enlarged anterior claw of the males, used to attract females