postabdomen noun2 •The part of a crustacean behind the cephalothorax. •The terminal segments of the abdomen of an insect, modified for reproduction.The postabdomens of both sexes of Cinderella lampra Steyskal and of the unique female of C. aczeli, n. sp. (Mendoza, Argentina) are described. — 1969 formspostabdomens · postabdomina