noun \ˈtrō-fə-ˌblast\

Definition of TROPHOBLAST

: the outer layer of the mammalian blastocyst that supplies nutrition to the embryo, facilitates implantation by eroding away the tissues of the uterus with which it comes in contact allowing the blastocyst to sink into the cavity formed in the uterine wall, and differentiates into the extraembryonic membranes surrounding the embryo—called also trophoderm
tro·pho·blas·tic \ˌtrō-fə-ˈblas-tik\ adjective

Seen & Heard

What made you want to look up trophoblast? Please tell us where you read or heard it (including the quote, if possible).