reversion vs u-turn

reversion and u-turn both are nouns.

Word	Noun	Adjective	Verb	Adverb
reversion	Yes	No	No	No
u-turn	Yes	No	No	No

As nouns, u-turn is a hyponym of reversion; that is, u-turn is a word with a more specific, narrower meaning than reversion:

Other hyponyms of reversion include about-face, about turn.

reversion (noun)	u-turn (noun)
a failure to maintain a higher state	complete reversal of direction of travel
turning in the opposite direction
returning to a former state
(genetics) a return to a normal phenotype (usually resulting from a second mutation)
a reappearance of an earlier characteristic
(law) an interest in an estate that reverts to the grantor (or his heirs) at the end of some period (e.g., the death of the grantee)