common salt vs flavouring

common salt and flavouring both are nouns.

Word	Noun	Adjective	Verb	Adverb
common salt	Yes	No	No	No
flavouring	Yes	No	No	No

As nouns, flavouring is a hypernym of common salt; that is, flavouring is a word with a broader meaning than common salt:

common salt: white crystalline form of especially sodium chloride used to season and preserve food
flavouring: something added to food primarily for the savor it imparts

Other hypernyms of common salt include flavorer, flavoring, flavourer, seasoner, seasoning.

common salt (noun)	flavouring (noun)
white crystalline form of especially sodium chloride used to season and preserve food	something added to food primarily for the savor it imparts
a white crystalline solid consisting mainly of sodium chloride (NaCl)