Regress is most usually a verb. The rather less usual [[noun] is pronounced differently.
- The verb 'to regress' is stressed on the second syllable: 'ti-GRESS', IPA: /rɪ ˈgres/. Its general meaning is 'to go back'. There are some more specific and precise meanings.
- In Psychology, it means 'to return to an earlier stage [of mental development]'; psycho-therapists may do this to their patients transitively ("The doctor regressed her to a time before the abuse began"), or people may regress intransitively, as sometimes a sick child may regress to thumb-sucking and other baby-ish behaviour.
- In statistics, certain techniques are known as regressions. To employ such techniques on data can be said to be regressing: one may regress measurements of one sort against measurements of another sort.
- In genetics and other sciences where statistics play a large part, 'a population may regress to the mean'. This is the phenomenon whereby, although individuals may show extremes in a particular characteristic, the offspring of such individuals will tend to a more 'average' position.
- The (rarer) noun 'a regress' is stressed on the first syllable, 'REE-gress', IPA: /ˈriː ˌgres/ is less often used than regression, which is the normal noun associated with the statistical and psychological uses of the verb. The noun regress itself is used in Law, in such phrases as 'ingress and regress' (~ going in and going out again); sometimes as an apparent slip for redress; in astronomy a a synonym for retrogradation, or the apparent moving backwards of the planets when seen against the stars; and other restricted technical meanings, in Philosophy, for example.