cleavage

(noun) the state of being split or cleft. Example: "There was a cleavage between the liberal and conservative members."

(noun) the breaking of a chemical bond in a molecule resulting in smaller molecules.

(noun) (embryology) the repeated division of a fertilised ovum. Synonyms: segmentation.

(noun) the line formed by a groove between two parts (especially the separation between a woman's breasts).

(noun) the act of cleaving or splitting.