yeast cake vs yeast

yeast cake and yeast both are nouns.

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

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

yeast cake: small cake of compressed moist yeast
yeast: 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 barm.

yeast cake (noun)	yeast (noun)
small cake of compressed moist yeast	any of various single-celled fungi that reproduce asexually by budding or division
	a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey