cleavage
cleav.age \'kle--vij\ n 1a: the quality of a crystallized substance or rock of splitting along defi nite planes 1b: a fragment (as of a diamond) obtained by splitting 2: the action of cleaving : the state of being cleft 3: cell division; esp : the series of mitotic divisions of the egg that results in the formation of the blastomeres and changes the single-celled zygote into a multicellular embryo