(1):
(n.) The act or state of growing worse, or the state of having become worse; decline; degradation; debasement; degeneracy; deterioration.
(2):
(n.) The thing degenerated.
(3):
(n.) That condition of a tissue or an organ in which its vitality has become either diminished or perverted; a substitution of a lower for a higher form of structure; as, fatty degeneration of the liver.
(4):
(n.) A gradual deterioration, from natural causes, of any class of animals or plants or any particular organ or organs; hereditary degradation of type.