aluminum vs potash alum

aluminum and potash alum both are nouns.

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

As nouns, potash alum is a hyponym of aluminum; that is, potash alum is a word with a more specific, narrower meaning than aluminum:

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

Other hyponyms of aluminum include alum, potassium alum, alum, ammonia alum, ammonium alum.

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