Cleavage

n.	1.	The act of cleaving or splitting.
	2.	(Crystallog.) 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.
	3.	(Geol.) Division into laminæ, like slate, with the lamination not necessarily parallel to the plane of deposition; - usually produced by pressure. Basal cleavage cleavage parallel to the base of a crystal, or to the plane of the lateral axes. Cell cleavage (Biol.) multiplication of cells by fission. See Segmentation. Cubic cleavage cleavage parallel to the faces of a cube. Diagonal cleavage cleavage parallel to ta diagonal plane. Egg clavage (Biol.) See Segmentation. Lateral cleavage cleavage parallel to the lateral planes. Octahedral cleavage cleavage parallel to the faces of an octahedron, dodecahedron, or rhombohedron. Prismatic cleavage cleavage parallel to a vertical prism.

Noun	1.	cleavage - the state of being split or cleft
	2.	cleavage - the breaking of a chemical bond in a molecule resulting in smaller molecules
	3.	cleavage - (embryology) the repeated division of a fertilised ovum Synonyms: segmentation
	4.	cleavage - the line formed by a groove between two parts (especially the separation between a woman's breasts)
	5.	cleavage - the act of cleaving or splitting

abscission, alienation, alpha decay, amputation, atom-chipping, atom-smashing, atomic disintegration, atomic reaction, atomization, beta decay, bombardment, breach, breach of friendship, break, breeding, bullet, butchering, chain reaction, chasm, chopping, cleft, cutting, dichotomy, disaffection, disfavor, disintegration series, disruption, dissociation, disunion, disunity, divergence, dividedness, division, enucleation, estrangement, exchange reaction, excision, falling-out, fission, fission reaction, gamma decay, ionization, laceration, mutilation, neutron reaction, nonreversible reaction, nuclear fission, nucleization, open rupture, photodisintegration, proton gun, proton reaction, recall of ambassadors, rending, resection, reversible reaction, rift, ripping, rupture, schism, scission, section, separation, severance, slashing, slicing, split, splitting, splitting the atom, stimulation, surgery, target, tearing, thermonuclear reaction