Pronunciation: (blas'chu-lu), [key]
—pl. -las, -laePronunciation: (-lē"). [key] Embryol.
the early developmental stage of an animal, following the morula stage and consisting of a single, spherical layer of cells enclosing a hollow, central cavity. Cf. blastocyst.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.