blasto-

Germination.

Greek blastos, germ or sprout.

Examples include blastocyst, a mammalian blastula (an embryo at the early stage of development when it is a hollow ball of cells) in which some differentiation of cells has occurred; blastoderm (Greek derma, skin), a blastula having the form of a disc of cells on top of the yolk; and blastomere (Greek meros, part), a cell formed by cleavage of a fertilized ovum.