cleavage

noun

cleav·​age ˈklē-vij 

1

a

: the quality of a crystallized substance or rock of splitting along definite planes

also : the occurrence of such splitting

b

: a fragment (as of a diamond) obtained by splitting

2

: the action of cleaving or splitting : the state of being cleft

3

: the series of synchronized mitotic cell divisions of a fertilized egg that results in the formation of the blastomeres and changes the single-celled zygote into a multicellular embryo

also : one of these cell divisions

4

: the splitting of a molecule into simpler molecules

5

: the depression between a woman's breasts especially when made visible by a low-cut neckline

Synonyms

• split
• dissolution
• breakup
• partition
• division
• separation

Examples of cleavage in a Sentence

The dress is cut low enough to reveal a lot of cleavage.

the cleavage between the rich and poor

the cleavages of an egg as an embryo develops

Recent Examples on the Web

In the cover image of the carousel, Sweeney posed solo on a rock formation set in the middle of a body of water while wearing a cleavage-baring one-piece black swimsuit with a zipper detail at her bust and black shades. —Angel Saunders, PEOPLE, 16 Sep. 2025

Japanese women are unlikely to buy a shirt that shows a lot of cleavage. —Lauren Collins, New Yorker, 15 Sep. 2025

Antonio and Stephanie are vibing about an expensive-looking outfit that will show off her cleavage. —Roxana Hadadi, Vulture, 12 Sep. 2025

Floating around the shins and with zero cleavage: now that’s my kind of good-girl dress. —Alexandra Pereira, Travel + Leisure, 18 Aug. 2025

Word History

First Known Use

1816, in the meaning defined at sense 1a

Phrases Containing cleavage

• discoidal cleavage
• radial cleavage
• spiral cleavage

Kids Definition

cleavage

noun

cleav·​age ˈklē-vij 

1

: the quality of a crystallized substance or rock of splitting in definite directions

2

: the action of cleaving : the state of being cleaved

3

: the series of mitotic cell divisions of a fertilized egg that changes the single cell into a many-celled embryo

Medical Definition

cleavage

noun

cleav·​age ˈklē-vij 

1

: the series of synchronized mitotic cell divisions of the fertilized egg that results in the formation of the blastomeres and changes the single-celled zygote into a multicellular embryo

also : one of these cell divisions

2

: the splitting of a molecule into simpler molecules