regression

2. In statistics, a way of finding how one thing changes when another thing changes.

The scientists used regression to predict sales from advertising spending.

3. In psychology, going back to childlike behavior when stressed.

Under pressure, the patient showed regression and began to act much younger.

4. In geology, the slow pulling back of the sea from the land.

The rock layers record a regression when the ancient sea shrank.

5. In medicine, the shrinking or improvement of a disease or growth.

The scan showed regression of the tumor after treatment.