blastocyst

English Thesaurus

1. the blastula of a placental mammal in which some differentiation of cells has occurred (noun.animal)

hypernym	:	blastosphere, blastula,
definition	:	early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is composed of a single layer of cells; during this stage (about eight days after fertilization) implantation in the wall of the uterus occurs (noun.animal)