sodium salicylate vs pain pill

sodium salicylate and pain pill both are nouns.

Word	Noun	Adjective	Verb	Adverb
sodium salicylate	Yes	No	No	No
pain pill	Yes	No	No	No

As nouns, pain pill is a hypernym of sodium salicylate; that is, pain pill is a word with a broader meaning than sodium salicylate:

Other hypernyms of sodium salicylate include analgesic, anodyne, painkiller.

sodium salicylate (noun)	pain pill (noun)
a crystalline salt used as an analgesic and antipyretic	a medicine used to relieve pain