urosome

Century Dictionary and Cyclopedia

1. n. In certain crustaceans, as the amphipods, the last three segments of the pleon or abdomen. Compare mesosome and metasome.
2. n. In biology: The last morphological segment of the tail; the terminal somatome of a vertebrate. See gephyrocercal.
3. n. The post-thoracic region of the body of arthropods; the abdomen or postabdomen as distinguished from the cephalothorax, and as composed of a series of urosomites or uromeres.

GNU Webster's 1913

1. n. The abdomen, or post-abdomen, of arthropods.