about turn vs reversal

about turn and reversal both are nouns.

Word	Noun	Adjective	Verb	Adverb
about turn	Yes	No	No	No
reversal	Yes	No	No	No

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

Other hypernyms of about turn include reverse, reversion, turnabout, turnaround.

about turn (noun)	reversal (noun)
act of pivoting 180 degrees, especially in a military formation	a change from one state to the opposite state
	the act of reversing the order or place of
	turning in the opposite direction
	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