wellerism vs rhetorical device

wellerism and rhetorical device both are nouns.

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

As nouns, rhetorical device is a hypernym of wellerism; that is, rhetorical device is a word with a broader meaning than wellerism:

wellerism: a comparison comprising a well-known quotation followed by a facetious sequel
rhetorical device: a use of language that creates a literary effect (but often without regard for literal significance)

wellerism (noun)	rhetorical device (noun)
a comparison comprising a well-known quotation followed by a facetious sequel	a use of language that creates a literary effect (but often without regard for literal significance)