In geology, the tendency of a rock, especially slate, to split along parallel or sub-parallel planes that result from realignment of component minerals during deformation or metamorphism.
1. The line formed by a groove between two parts (especially the separation between a woman's breasts).
2. The breaking of a chemical bond in a molecule resulting in smaller molecules.
3. (Embryology) The repeated division of a fertilised ovum; SYN. segmentation.