sweet bay vs magnolia

sweet bay and magnolia both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet bay	Yes	No	No	No
magnolia	Yes	No	No	No

As nouns, magnolia is a hypernym of sweet bay; that is, magnolia is a word with a broader meaning than sweet bay:

sweet bay: shrub or small tree having rather small fragrant white flowers; abundant in southeastern United States
magnolia: any shrub or tree of the genus Magnolia; valued for their longevity and exquisite fragrant blooms

sweet bay (noun)	magnolia (noun)
shrub or small tree having rather small fragrant white flowers; abundant in southeastern United States	any shrub or tree of the genus Magnolia; valued for their longevity and exquisite fragrant blooms
	dried bark of various magnolias; used in folk medicine