(1) A condition of a blastula in which there are three primary germ layers: ectoderm, mesoderm and endoderm.
(2) A condition of an ovum in which it divides forming a blastoderm made up of three layers.
All higher and intermediate animals (i.e. from flat worms to humans develop from a triploblastic embryo.
Word origin: Greek tripló(os), threefold + blastikós, budding.
Related forms: triploblastic (adjective).
See also: blastula, germ layer.