Involution

Involution: 1. Literally, a turning inward or rolling inward.
2. A decrease in size, usually after an increase. The uterus involutes after pregnancy.
3. A retrograde change. After treatment, a tumor may involute.
4. With advancing age, there may be physical and emotional involution. This process has also been called senile involution.
From the Latin involutio, from in- meaning into + volvere meaning to roll.