from
The Collaborative International Dictionary of English v.0.48
Cleavage \Cleav"age\, n.
1. The act of cleaving or splitting.
[1913 Webster]
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}.
[1913 Webster]
3. (Geol.) Division into lamin[ae], like slate, with the
lamination not necessarily parallel to the plane of
deposition; -- usually produced by pressure.
[1913 Webster]
{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}, {Dodecahedral cleavage}, or
{Rhombohedral cleavage}, cleavage parallel to the faces of an
octahedron, dodecahedron, or rhombohedron.
{Prismatic cleavage}, cleavage parallel to a vertical prism.
[1913 Webster]