potash alum vs Al

potash alum and Al both are nouns.

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

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

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

Other hypernyms of potash alum include aluminium, aluminum, atomic number 13, double salt.

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