lightening vs change of color

lightening and change of color both are nouns.

Word	Noun	Adjective	Verb	Adverb
lightening	Yes	No	No	No
change of color	Yes	No	No	No

As nouns, change of color is a hypernym of lightening; that is, change of color is a word with a broader meaning than lightening:

lightening (noun)	change of color (noun)
changing to a lighter color	an act that changes the light that something reflects
descent of the uterus into the pelvic cavity that occurs late in pregnancy; the fetus is said to have dropped