1a sharp division; a split:the old cleavage between the forces of the right and left
[mass noun] Biology cell division, especially of a fertilized egg cell:the cell undergoes cleavage and segmentation and develops into a blastula [count noun]:all the cells divide synchronously for the first 12 cleavages
[mass noun] the splitting of rocks or crystals in a preferred plane or direction:true slates split easily along a plane of cleavage
2the hollow between a woman’s breasts when supported, especially as exposed by a low-cut garment:Holly and Bridget checked their cleavages and rearranged their hair [mass noun]: she wore a dress that exposed an inch or two of cleavage
