What is "lateral cleavage"

Lateral \Lat"er*al\, a. [L. lateralis, fr. latus, lateris, side: cf. F. lat['e]ral.]

1. Of or pertaining to the sides; as, the lateral walls of a house; the lateral branches of a tree.

2. (Anat.) Lying at, or extending toward, the side; away from the mesial plane; external; -- opposed to mesial.

3. Directed to the side; as, a lateral view of a thing.

   Lateral cleavage (Crystallog.), cleavage parallel to the lateral planes.

   Lateral equation (Math.), an equation of the first degree.

   Lateral line (Anat.), in fishes, a line of sensory organs along either side of the body, often marked by a distinct line of color.

   Lateral pressure or stress (Mech.), a pressure or stress at right angles to the length, as of a beam or bridge; -- distinguished from longitudinal pressure or stress.

   Lateral strength (Mech.), strength which resists a tendency to fracture arising from lateral pressure.

   Lateral system (Bridge Building), the system of horizontal braces (as between two vertical trusses) by which lateral stiffness is secured.

Cleavage \Cleav"age\, 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 lamin[ae], 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, Dodecahedral cleavage, or Rhombohedral cleavage, cleavage parallel to the faces of an octahedron, dodecahedron, or rhombohedron.

   Prismatic cleavage, cleavage parallel to a vertical prism.