

DECAY
[verb]
1. to become decomposed; rot.
2. to decline in excellence, prosperity, health, etc.; deteriorate.
[noun]
3. decomposition; disintegration; rot.
4. a gradual falling into an inferior condition; progressive decline.
5. decline in or loss of strength, health, intellect, etc.
6. Physics: a radioactive process in which a nucleus undergoes spontaneous transformation into one or more different nuclei and simultaneously emits radiation, loses electrons, or undergoes fission.
7. Aerospace: the progressive, accelerating reduction in orbital parameters, particularly apogee and perigee, of a spacecraft due to atmospheric drag.

