yeast cake vs barm

yeast cake and barm both are nouns.

Word	Noun	Adjective	Verb	Adverb
yeast cake	Yes	No	No	No
barm	Yes	No	No	No

As nouns, barm is a hypernym of yeast cake; that is, barm is a word with a broader meaning than yeast cake:

yeast cake: small cake of compressed moist yeast
barm: a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey

Other hypernyms of yeast cake include yeast.

yeast cake (noun)	barm (noun)
small cake of compressed moist yeast	a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey