blastomere
noun
blas·to·mere ˈbla-stə-ˌmir 
: one of the cells that are produced during cleavage of a zygote and that form the morula
Example Sentences
Recent Examples on the Web First, the isolated cell can be co-cultured with blastomeres from other embryos biopsied during the IVF cycle (there are almost always multiple embryos undergoing PGD biopsy per cycle). 
Wired Blogs, WIRED, 21 Sep. 2006
Wired Blogs, WIRED, 21 Sep. 2006 Word History
Etymology
blasto- + -mere
First Known Use
1875, in the meaning defined above
Medical Definition
blastomere
noun
blas·to·mere ˈblas-tə-ˌmi(ə)r
: a cell produced during cleavage of a fertilized egg
called also cleavage cell