noun. the blastula of a placental mammal in which some differentiation of cells has occurred.
- blastodermic vessicle
- blasto- (English)
- βλαστός (Ancient Greek (to 1453))
- cyst (English)
- cystis (Latin)
Example sentences of the word blastocyst
1. Noun, singular or mass
Embryonic stem cells are found in the cell mast of a blastocyst.