What is Crabs?

Crabs definition and meaning on Dictionary terms:
any decapod crustacean of the suborder Brachyura, having the eyes on short stalks and a short, broad, more or less flattened body, the abdomen being small and folded under the thorax.
any of various other crustaceans, as the hermit crab, or other animals, as the horseshoe crab, resembling the true crabs.

(initial capital letter) Astronomy, Astrology. the zodiacal constellation or sign Cancer.
(initial capital letter) Astronomy. the Crab Nebula.
any of various mechanical contrivances for hoisting or pulling.
Aeronautics. the maneuver of crabbing.
Informal. the crab louse.See under louse(def 1).
crabs, (used with a singular verb)a losing throw, as two aces, in the game of hazard.pediculosis.

verb (used without object), crabbed, crab