A crab is any of various crustaceans with four pairs of legs, a pair of pincers, a flattish shell, and a short, broad abdomen folded under its thorax. Several similar animals, such as the crab louse, or the hermit crab[?], are also called crabs.
A crab is any of various machines used to hoist heavy objects.
... tube that connects the urinary bladder to the outside of the body. The urethra has an excretory function in both sexes, to pass urine to the outside, and also a reproductive ...