Cleavage
In embryology, cleavage is the division of cells in the early embryo. The zygotes of many species undergo rapid cell cycles with no significant growth, producing a cluster of cells the same size as the original zygote.
In mineralogy, the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types:
- Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes.
- Cubic cleavage: cleavage parallel to the faces of a cube.
- Diagonal cleavage: cleavage parallel to a diagonal plane.
- Lateral cleavage: cleavage parallel to the lateral planes.
- Octahedral, Dodecahedral, or Rhombohedral cleavage: cleavage parallel to the faces of an octahedron, dodecahedron, or rhombohedron.
- Prismatic cleavage, cleavage parallel to a vertical Prism.
See Crystal structure.
In general use, the separation between a woman's breasts, or any line formed by a groove between two parts.
