regression vs reversal

regression and reversal both are nouns.

Word	Noun	Adjective	Verb	Adverb
regression	Yes	No	No	No
reversal	Yes	No	No	No

As nouns, reversal is a hypernym of regression; that is, reversal is a word with a broader meaning than regression:

regression (noun)	reversal (noun)
returning to a former state	a change from one state to the opposite state
the relation between selected values of x and observed values of y (from which the most probable value of y can be predicted for any value of x)	the act of reversing the order or place of
(psychiatry) a defense mechanism in which you flee from reality by assuming a more infantile state	turning in the opposite direction
an abnormal state in which development has stopped prematurely	a major change in attitude or principle or point of view
	a judgment by a higher court that the judgment of a lower court was incorrect and should be set aside
	a decision to reverse an earlier decision
	turning in an opposite direction or position
	an unfortunate happening that hinders or impedes; something that is thwarting or frustrating