Definition of cleavage:

• Division into laminae, like slate, with the lamination not necessarily parallel to the plane of deposition; -- usually produced by pressure.
• the state of being split or cleft
• the line formed by a groove between two parts ( especially the separation between a woman's breasts)
• the breaking of a chemical bond in a molecule resulting in smaller molecules
• The act of cleaving or splitting.
• The quality possessed by many crystallized substances of splitting readily in one or more definite directions, in which the cohesive attraction is a minimum, affording more or less smooth surfaces; the direction of the dividing plane; a fragment obtained by cleaving, as of a diamond. See Parting.
• Division into laminae, like slate, with the lamination not necessarily parallel to the plane of deposition; - usually produced by pressure.
• The act of splitting; the property of some minerals and rocks of being divided into layers.
• 1. The splitting up of a complex molecule into two or more simpler molecules. 2. Segmentation of the vitellus, yolk- c.
• Act or manner of cleaving or splitting.
• Manner or direction of splitting.
• A splitting or tendency to split; a split; cleft; division.
• The act of cleaving or splitting; the fracture, or particular manner, in which any mineral, having a regular structure, may be cleaved.
• That structure in many stratified rocks, such as clay- slate, which renders them capable of being split indefinitely into thin plates.
• [ Anglo-Saxon] The series of karyokinetic divisions which change the egg into a multicellular embryo.

Usage examples for cleavage

1. Bakewell, Mr., on cleavage in Swiss Alps.  The Student's Elements of Geology by Sir Charles Lyell

2. The vital lines of cleavage among our people do not correspond, and indeed run at right angles to, the lines of cleavage which divide occupation from occupation, which divide wage- workers from capitalists, farmers from bankers, men of small means from men of large means, men who live in the towns from men who live in the country; for the vital line of cleavage is the line which divides the honest man who tries to do well by his neighbor from the dishonest man who does ill by his neighbor.  Complete State of the Union Addresses from 1790 to the Present by Various

3. But it is, of course, impossible to state beforehand what will be the precise line of cleavage or what form the division between the two parties in interest will take.  An Inquiry Into The Nature Of Peace And The Terms Of Its Perpetuation by Thorstein Veblen

4. At no time in the Christian past had there been such a deep and wide cleavage in humanity.  Gilbert Keith Chesterton by Maisie Ward