mustard seed vs flavouring

mustard seed and flavouring both are nouns.

Word	Noun	Adjective	Verb	Adverb
mustard seed	Yes	No	No	No
flavouring	Yes	No	No	No

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

Other hypernyms of mustard seed include flavorer, flavoring, flavourer, seasoner, seasoning.

mustard seed (noun)	flavouring (noun)
black or white seeds ground to make mustard pastes or powders	something added to food primarily for the savor it imparts