Gastrula
Pronunciation : Gas"tru*la
Part of Speech : n.;
Etymology : [NL., dim. fr. Gr. (Biol.)
Definition : Defn: 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 Gastr?a. -- a.
Defn: Of or pertaining to a gastrula.
pl. Gastrul
Source : Webster's Unabridged Dictionary, 1913