Aids implantation in the uterine wall

• The membrane that forms the wall of the blastocyst in early development

Wiktionary Word definitions in Wiktionary
n. (context cytology English) The membrane of cells that forms the wall of a blastocyst during early pregnancy, providing nutrients to the embryo and later developing into part of the placenta.

WordNet Word definitions in WordNet
n. the membrane that forms the wall of the blastocyst in early development; aids implantation in the uterine wall; "after implantation of the blastocyst in the uterine wall the trophoblast divides into two layers, the chorion and the placenta"

Wikipedia Word definitions in Wikipedia
Trophoblasts (from Greek trephein : to feed, and blastos : germinator) are cells forming the outer layer of a blastocyst , which provide nutrients to the embryo and develop into a large part of the placenta . They are formed during the first stage of pregnancy ...