gastrulate

‖n.; pl. Gastrulæ ety>[ NL., dim. fr. Gr. &unr_; the stomach. ] (Biol.) An embryonic form having its origin in the invagination or pushing in of the wall of the planula or blastula (the blastosphere) on one side, thus giving rise to a double-walled sac, with one opening or mouth (the blastopore) which leads into the cavity (the archenteron) lined by the inner wall (the hypoblast). See Illust. under Invagination. In a more general sense, an ideal stage in embryonic development. See Gastræa. -- a. Of or pertaining to a gastrula. [ 1913 Webster ]