1. the act of cleaving or splitting.
  2. the state of being cleft.
  3. the area between a woman's breasts, especially when revealed by a low-cut neckline.
  4. a critical division in opinion, beliefs, interests, etc., as leading to opposition between two groups: a growing cleavage between the Conservative and Liberal wings of the party.
  5. the tendency of crystals, certain minerals, rocks, etc., to break in preferred directions so as to yield more or less smooth surfaces (cleavage planes).
  6. Embryology. the total or partial division of the egg into smaller cells or blastomeres.
  7. Also called scission. Chemistry. the breaking down of a molecule or compound into simpler structures.

Origin of cleavage

First recorded in 1810–20; cleave2 + -age Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for cleavages

Contemporary Examples of cleavages

Historical Examples of cleavages

  • They were cloven, it was true, but the cleavages were great ulcers and livid putrefactions.

  • They are triclinic, with cleavages meeting at approximately 86 degrees.


    William J. Miller

  • All these cleavages and divisions in the population continue in their effects to this day.

    The Quaker Colonies

    Sydney G. Fisher

  • (c) That it is useless to further harp on the “cleavages” of race, religion and language, in dealing with the problem of India.

  • The cleavages of racial temperament are not, as in other countries, bridged over by a sense of national unity.

    One Irish Summer

    William Eleroy Curtis

British Dictionary definitions for cleavages


  1. informal the separation between a woman's breasts, esp as revealed by a low-cut dress
  2. a division or split
  3. (of crystals) the act of splitting or the tendency to split along definite planes so as to yield smooth surfaces
  4. Also called: segmentation embryol (in animals) the repeated division of a fertilized ovum into a solid ball of cells (a morula), which later becomes hollow (a blastula)
  5. the breaking of a chemical bond in a molecule to give smaller molecules or radicals
  6. geology the natural splitting of certain rocks, or minerals such as slates, or micas along the planes of weakness
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for cleavages



1816, in geology, "action of splitting (rocks or gems) along natural fissures," from cleave (v.1) + -age. General meaning "action or state of cleaving or being cleft" is from 1867.

The sense of "cleft between a woman's breasts in low-cut clothing" is first recorded 1946, defined in a "Time" magazine article [Aug. 5] as the "Johnston Office trade term for the shadowed depression dividing an actress' bosom into two distinct sections;" traditionally first used in this sense by U.S. publicist Joseph I. Breen (1888-1965), head of the Production Code Administration (replaced 1945 by Eric Johnston), enforcers of Hollywood self-censorship, in reference to Jane Russell's costumes and poses in "The Outlaw."

Online Etymology Dictionary, © 2010 Douglas Harper

cleavages in Medicine


  1. A series of cell divisions in the ovum immediately following fertilization.segmentation
  2. The splitting of a complex molecule into two or more simpler molecules.scission
  3. The linear clefts in the skin, indicating the general direction of the fibers in the dermis.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

cleavages in Science


  1. Geology The breaking of certain minerals along specific planes, making smooth surfaces. These surfaces are parallel to the faces of the molecular crystals that make up the minerals. A mineral that exhibits cleavage breaks into smooth pieces with the same pattern of parallel surfaces regardless of how many times it is broken. Some minerals, like quartz, do not have a cleavage and break into uneven pieces with rough surfaces.
  2. Biology
    1. The series of mitotic cell divisions by which a single fertilized egg cell becomes a many-celled blastula. Each division produces cells half the size of the parent cell.
    2. Any of the single cell divisions in such a series.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

cleavages in Culture


The process by which an animal cell divides into two daughter cells after mitosis. In an embryo, this process is repeated many times and leads to the formation of the blastula.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.