1. The loss of vitality in or the degeneration of certain cells or tissues, as in the aging process; physical degeneration; loss of vitality: The loss of functions or vitality in an organism or in cells or tissues which is not a result of any apparent injury; for example, senile dementia and related abiotrophies.
2. Progressive loss of vitality of certain tissues or organs leading to disorders or losses of functions: The abiotrophy of the heart may be appreciably shorter than that of other organs of the body which can lead to early disturbances in activities that upset other bodily organs.