Crazing occurs through the process of contraction and expansion of the body and glaze at different rates, sometimes referred to as secondary crackle. Usually the word crackle is used when the effect was intended as a decoratice effect. The word 'crazing' are usually used when the effect was unintended and might have appeared randomly and over time. More jokingly one have said that crackles and crazing are cracks that occurs in the glaze. If you like it, it is crackles and if you don't like it, it is crazing.