Cleav'age, n.
n. 1. The act of cleaving or splitting.
Sense 2. (Crystallog.) The quality of splitting or dividing naturally; direction of dividing plane.
Sense 3. (Geol.) Division into laminæ, like slate, with the lamination not parallel to the plane of deposition.
Basal cleavage, cleavage parallel to the base of a crystal, or the plane of the lateral axes. — Cubic cleavage, that parallel to the faces of a cube. — Diagonal cleavage, that parallel to a diagonal plane. — Lateral cleavage (called also peritomous cleavage), that parallel to the lateral planes. Dana.