potassium alum vs aluminum

potassium alum and aluminum both are nouns.

Word	Noun	Adjective	Verb	Adverb
potassium alum	Yes	No	No	No
aluminum	Yes	No	No	No

As nouns, aluminum is a hypernym of potassium alum; that is, aluminum is a word with a broader meaning than potassium alum:

potassium alum: a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum
aluminum: a silvery ductile metallic element found primarily in bauxite

Other hypernyms of potassium alum include Al, aluminium, atomic number 13, double salt.

potassium alum (noun)	aluminum (noun)
a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum	a silvery ductile metallic element found primarily in bauxite