Lobster's limb

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Uropod \U"ro*pod\, n. [2d uro- + -pod.] (Zo["o]l.) Any one of the abdominal appendages of a crustacean, especially one of the posterior ones, which are often larger than the rest, and different in structure, and are used chiefly in locomotion. See Illust. ...

Wikipedia Word definitions in Wikipedia
Uropods , in immunology , refer to the hind part of polarized leukocytes , mostly involved in cell-to-cell interaction, cell activation and apoptosis . Leukocyte polarization is an important requirement for migration, activation and apoptosis.

Wiktionary Word definitions in Wiktionary
n. 1 (context anatomy English) either of the two posterior abdominal appendages of the lobster, shrimp and some other crustaceans 2 (context immunology English) the hind part of polarized leukocytes, mostly involved in cell-to-cell interaction, cell activation ...