cleav·age 
/ˈkli:vɪʤ/ noun
plural cleav·ag·es /ˈkli:vɪʤ/ noun 1 [noncount] informal : the space between a woman's breasts especially when it can be easily seen
▪ The dress is cut low enough to reveal a lot of cleavage. 2 : a division between two things or groups [noncount] ▪ the cleavage between the rich and poor [count] ▪ social cleavages 3 [count] technical : the act of splitting apart
▪ the cleavages of an egg as an embryo develops
▪ The dress is cut low enough to reveal a lot of cleavage.
▪ the cleavages of an egg as an embryo develops
