blastocyst

[blas-tuh-sist]

noun Embryology.

the blastula of the mammalian embryo, consisting of an inner cell mass, a cavity, and an outer layer, the trophoblast.

Origin of blastocyst

First recorded in 1885–90; blasto- + -cyst

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for blastocyst

blastocyst

noun embryol

Also called: blastosphere the blastula of mammals: a sphere of cells (trophoblast) enclosing an inner mass of cells and a fluid-filled cavity (blastocoel)

another name for germinal vesicle

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for blastocyst

1876, from blasto- + cyst.

blastocyst in Medicine

blastocyst

[blăs′tə-sĭst′]

n.

The modified blastula stage of mammalian embryos, consisting of the inner cell mass and a thin trophoblast layer enclosing the blastocoel.blastodermic vesicle

Related formsblas′to•cys′tic adj.

blastocyst in Science

blastocyst

[blăs′tə-sĭst′]

The modified blastula that is characteristic of placental mammals. It has an outer layer, known as a trophoblast, that participates in the development of the placenta. The inner layer of cells develops into the embryo.