cleavage

Noun

cleavage (countable and uncountable, plural cleavages)

1. The act of cleaving or the state of being cleft.
   • Mineral cleavage is a property of cohesion. The cleavage of the particles themselves and its attitude with reference to the plane of the greatest and mean dimensional axes help to determine the perfection of rock cleavage. The more nearly parallel to the greater dimensions of the particle, and the...1905, Charles Kenneth Leith, “The Observed Relation of Secondary Rock Cleavage to the Parallel Arrangement of Mineral Particles”, in Rock Cleavage (United States Geological Survey Bulletin; no. 239)...
   • […] the forces — the internal cleavages over class differences, the desire for "the good life," the white racist flight from the die schwartze — which shattered Jewish working-class community in the generation before mine.1985 August 24, Robert Butler, “Sex More Punished Than Murder”, in Gay Community News, volume 13, number 7, page 5
2. The hollow or separation between a woman's breasts, especially as revealed by a low neckline.
   • Holonym: décolletage
   • Low-cut Restoration costumes worn by the Misses Lockwood and Roc (see cut) display too much "cleavage" (Johnston Office trade term for the shadowed depression dividing an actress' bosom into two distinct sections).1946 August 5, “Cinema: Cleavage and the Code”, in Time

   Synonyms:

   intermammary sulcus

3. (broadly) Any similar separation between two body parts, such as the buttocks or toes.
   • Half an hour later, she was staring at a large bottom-cleavage, which was protruding from under the bed. / 'Ohhh Kayyy. Here we go. This is basically your problem.' / Olivia took a few steps back as the bottom-cleavage started wriggling out towards her. Connor the counter-surveillance expert pulled...2003, Helen Fielding, Olivia Joules and the Overactive Imagination, London: Picador, →ISBN, page 95
   • Brenda lifted the top off a shoebox and dug beneath the tissue paper, unearthing a two-toned, turquoise-and-cream, high-heeled pump. "This is one of my favorites," she said, balancing it in the palm of her hand. "I love shoes that show toe cleavage." / "Toe cleavage?" / Brenda kicked off a leather...2014, Bridgett M. Davis, Into the Go-Slow, New York, N.Y.: The Feminist Press at the City University of New York, →ISBN
4. The repeated division of a cell into daughter cells after mitosis.
   • [C]itellate annelids (leeches + oligochaetes) provide solid ground for comparative analyses, because they form a monophyletic group within the paraphyletic polychaetes[…]. […] The unequal cleavage of the zygote followed by the unequal cleavage of the CD cell is critical for D-quadrant specification...2008 spring, Dierdre Colleen Lyons, “Mechanisms Controlling the Asymmetric Second Cleavage”, in Mechanisms Controlling the Asymmetric Second Cleavage in the Helobdella Embryo (unpublished Ph.D. in...
5. The splitting of a large molecule into smaller ones.
   • Carotenoid cleavage oxygenases (CCOs) are a class of enzymes that oxidatively cleave carotenoids into apocarotenoids. Carotenoid cleavage oxygenases have been identified in plants and animals and produce a wide range of cleavage products. […] Two of the three enzymes showed cleavage of β...2006, E. K. Marasco, K. Vay, C. Schmidt-Dannert, “Identification of Carotenoid Cleavage Oxygenases from Nostoc sp. PCC7120 with Different Cleavage Activities”, in Journal of Biological Chemistry...
6. The tendency of a crystal to split along specific planes; schistosity.
   • Notice that cleavage has nothing to do with imperfections in the crystal. Indeed, if you try cleaving an imperfect crystal, you may find that it cannot be cleaved as well as a perfect one. The cleavage is the result of the orderliness of the atomic arrangement. No wonder imperfections, which...1982, Alan Holden, Phylis Morrison, “Cleaving and Gliding Crystals”, in Crystals and Crystal Growing, Cambridge, Mass.; London: MIT Press, →ISBN, page 202
7. The division of voters into voting blocs.
   • A voting bloc in Congress can represent a long-standing alliance or can be created anew as a result of the increased saliency of a particular issue, such as war or a severe economic downturn. A division between voting blocs is called a cleavage and because voting blocs are impermanent, dominant...2011, Scot Schraufnagel, “Voting bloc”, in Historical Dictionary of the U.S. Congress, Lanham, Md.: Scarecrow Press, →ISBN, page 235
   • The Kremlin has appointed graduates of the federal "Time of Heroes" programs to high level positions in the Russian federal, regional, and local governments -- likely to militarize Russian society and prevent veterans from becoming a disenfranchised political cleavage that could pose a risk to the...2025 March 24, Christina Harward, Angelica Evans, Grace Mappes, Olivia Gibson, Daria Novikov, George Barros, Nate Trotter, “Russian Offensive Campaign Assessment, March 24, 2025”, in Ukraine Project...