UROPOD
Etymology
Noun
uropod (plural uropods)
(anatomy) either of the two posterior abdominal appendages of the lobster, shrimp and some other crustaceans
(immunology) the hind part of polarized leukocytes, mostly involved in cell-to-cell interaction, cell activation and apoptosis
Source: Wiktionary
U"ro*pod, n. Etym: [2d uro- + -pod.] (Zoöl.)
Definition: 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. of Crustacea, and Stomapoda.
Source: Webster’s Unabridged Dictionary 1913 Edition