What is the term for the wasting away of a body part or tissue?

The term for the wasting away of a body part or tissue is atrophy. Atrophy refers to the reduction in size or wasting away of a tissue or organ, which can occur for a variety of reasons, including disuse, lack of nourishment, or diseases that affect muscle and broader body systems. This physiological process reflects the body's ability to adapt to changes in conditions or demand, reducing the resources allocated to that tissue or organ when it’s no longer needed or utilized.

Hypertrophy, on the other hand, describes the increase in the size of an organ or tissue, typically due to an increase in the size of its cells, and occurs in response to increased workload or stress.

Apoplexy is an outdated medical term that historically referred to sudden incapacitation, often from a stroke, rather than a process of tissue wasting.

Necrosis refers to the death of cells or tissues due to disease, injury, or lack of blood supply, which is a different process than atrophy as it implies cell death rather than a reduction in cell size or function.

Thus, atrophy accurately describes the process of body part or tissue wasting away.