acid dye vs dyestuff

acid dye and dyestuff both are nouns.

Word	Noun	Adjective	Verb	Adverb
acid dye	Yes	No	No	No
dyestuff	Yes	No	No	No

As nouns, dyestuff is a hypernym of acid dye; that is, dyestuff is a word with a broader meaning than acid dye:

acid dye: dye in which the chromophore is part of a negative ion
dyestuff: a usually soluble substance for staining or coloring e.g. fabrics or hair

Other hypernyms of acid dye include dye.

acid dye (noun)	dyestuff (noun)
dye in which the chromophore is part of a negative ion	a usually soluble substance for staining or coloring e.g. fabrics or hair