regression

(rĭ-grĕshˈən)

1. Reversion; retrogression.
2. Relapse to a less perfect or developed state.
3. Psychology Reversion to an earlier or less mature pattern of feeling or behavior.
4. Medicine A subsidence of the symptoms or process of a disease.
5. Biology The return of a population to an earlier or less complex physical type in successive generations.
6. Statistics The relationship between the mean value of a random variable and the corresponding values of one or more independent variables.
7. Astronomy Retrograde motion of a celestial body.
8. Geology A relative fall in sea level resulting in deposition of terrestrial strata over marine strata.