What term describes a decrease in organ or tissue size due to disease or lack of use?

The term that accurately describes a decrease in organ or tissue size due to disease or lack of use is atrophy. Atrophy involves the reduction in the size of cells, which subsequently leads to a decrease in the overall size of the affected tissue or organ. This can occur for various reasons, including disuse, aging, or a pathological condition where there is inadequate nutrition or blood supply.

In contrast, hypertrophy refers to an increase in the size of cells and, consequently, an increase in the size of the organ or tissue, often in response to increased workload. Hyperplasia is characterized by an increase in the number of cells, resulting in the enlargement of a tissue or organ, which can occur in response to stimuli such as hormonal changes. Necrosis involves the death of cells or tissue in a living organism and does not refer specifically to size reduction due to disuse or disease. Therefore, atrophy distinctly aligns with the concept of a decrease in size caused by various factors.