Fraser fir vs silver fir

Fraser fir and silver fir both are nouns.

Word	Noun	Adjective	Verb	Adverb
Fraser fir	Yes	No	No	No
silver fir	Yes	No	No	No

As nouns, silver fir is a hypernym of Fraser fir; that is, silver fir is a word with a broader meaning than Fraser fir:

Fraser fir: small fast-growing but short-lived fir of southern Alleghenies similar to balsam fir but with very short leaves
silver fir: any of various true firs having leaves white or silvery white beneath

Fraser fir (noun)	silver fir (noun)
small fast-growing but short-lived fir of southern Alleghenies similar to balsam fir but with very short leaves	any of various true firs having leaves white or silvery white beneath