Source : Webster's Revised Unabridged Dictionary (1913)
Blastula \Blas"tu*la\, n. [NL., dim. of Gr. blasto`s a sprout.]
(Biol.)
That stage in the development of the ovum in which the outer
cells of the morula become more defined and form the
blastoderm.
Source : WordNet®
blastula
n : 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 [syn: {blastodermic vesicle}]
[also: {blastulae} (pl)]