any of several crabs that live along rocky beaches, especially those of the genus Cancer, as C. irroratus, of the eastern coast of North America, having the rear legs modified for running.
Origin of rock crab
An Americanism dating back to 1830–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for rock crab
Historical Examples of rock crab
In the little hollows between rocks a rock-crab or a green-crab may be found on guard.