hydrogel vs gel

hydrogel and gel both are nouns.

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

As nouns, gel is a hypernym of hydrogel; that is, gel is a word with a broader meaning than hydrogel:

Other hypernyms of hydrogel include colloidal gel.

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

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