blastula Meaning, Definition & Usage

  1. noun early stage of an embryo produced by cleavage of an ovum; a liquid-filled sphere whose wall is composed of a single layer of cells; during this stage (about eight days after fertilization) implantation in the wall of the uterus occurs
    blastosphere.

WordNet

Blas"tu*la noun
Etymology
NL., dim. of Gr. a sprout.
Definitions
  1. (Biol.) That stage in the development of the ovum in which the outer cells of the morula become more defined and form the blastoderm.

Webster 1913