elocutionist vs rhetorician

elocutionist and rhetorician both are nouns.

Word	Noun	Adjective	Verb	Adverb
elocutionist	Yes	No	No	No
rhetorician	Yes	No	No	No

As nouns, rhetorician is a hypernym of elocutionist; that is, rhetorician is a word with a broader meaning than elocutionist:

elocutionist: a public speaker trained in voice production and gesture and delivery
rhetorician: a person who delivers a speech or oration

Other hypernyms of elocutionist include orator, public speaker, speechifier, speechmaker.

elocutionist (noun)	rhetorician (noun)
a public speaker trained in voice production and gesture and delivery	a person who delivers a speech or oration