poliosis vs depigmentation

poliosis and depigmentation both are nouns.

Word	Noun	Adjective	Verb	Adverb
poliosis	Yes	No	No	No
depigmentation	Yes	No	No	No

As nouns, depigmentation is a hypernym of poliosis; that is, depigmentation is a word with a broader meaning than poliosis:

poliosis: loss of color from the hair
depigmentation: absence or loss of pigmentation (or less than normal pigmentation) in the skin or hair

poliosis (noun)	depigmentation (noun)
loss of color from the hair	absence or loss of pigmentation (or less than normal pigmentation) in the skin or hair