Calcification is the process in which calcium salts build up in body tissue, leading to a hardening or stiffening of the affected area. This can occur in various tissues, including bones, arteries, and organs, and can be a normal part of aging or a response to injury or disease. In some cases, pathological calcification can contribute to conditions like atherosclerosis or kidney stones. Overall, calcification plays a crucial role in both normal physiological processes and certain medical conditions.