gel vs hydrogel

gel and hydrogel both are nouns.

Word	Noun	Adjective	Verb	Adverb
gel	Yes	No	Yes	No
hydrogel	Yes	No	No	No

As nouns, hydrogel is a hyponym of gel; that is, hydrogel is a word with a more specific, narrower meaning than gel:

gel (noun)	hydrogel (noun)
a thin translucent membrane used over stage lights for color effects	a colloidal gel in which water is the dispersion medium
jellylike substance used in hair styling
a colloid in a more solid form than a sol

gel (verb)	hydrogel (verb)
apply a styling gel to
become a gel