noun
- an early stage of embryonic development in mammals, consisting of a hollow ball of cells that implants in the uterine wall
Usage: biology; embryology
Examples
- The blastocyst forms about five days after fertilization.
- Scientists can extract stem cells from the blastocyst stage.
- The blastocyst must successfully implant in the uterus for pregnancy to continue.
- Researchers study blastocysts to understand early human development.
- In vitro fertilization involves transferring blastocysts to the mother’s womb.
- The blastocyst contains both the inner cell mass and the outer layer.