Definition of "Cleavage" :

noun: the act of cleaving or splitting

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

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

noun: the breaking of a chemical bond in a molecule resulting in smaller molecules

noun: the state of being split or cleft

"There was a cleavage between the liberal and conservative members."