Blastula

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  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.
     [1913 Webster]



From WordNet (r) 2.0 [wn]:

  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)]