yeast vs brewer's yeast

yeast and brewer's yeast both are nouns.

Word	Noun	Adjective	Verb	Adverb
yeast	Yes	No	No	No
brewer's yeast	Yes	No	No	No

As nouns, brewer's yeast is a hyponym of yeast; that is, brewer's yeast is a word with a more specific, narrower meaning than yeast:

yeast: any of various single-celled fungi that reproduce asexually by budding or division
brewer's yeast: used as a leaven in baking and brewing

As nouns, brewer's yeast is a hyponym of yeast; that is, brewer's yeast is a word with a more specific, narrower meaning than yeast:

yeast: a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey
brewer's yeast: yeast used in fermenting beer

Other hyponyms of yeast include yeast cake, mother.

yeast (noun)	brewer's yeast (noun)
any of various single-celled fungi that reproduce asexually by budding or division	used as a leaven in baking and brewing
a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey	yeast used in fermenting beer