rhetoric vs rhetorical device

rhetoric and rhetorical device both are nouns.

Word	Noun	Adjective	Verb	Adverb
rhetoric	Yes	No	No	No
rhetorical device	Yes	No	No	No

rhetoric (noun)	rhetorical device (noun)
study of the technique and rules for using language effectively (especially in public speaking)	a use of language that creates a literary effect (but often without regard for literal significance)
using language effectively to please or persuade
high-flown style; excessive use of verbal ornamentation
loud and confused and empty talk