soundboard vs cavity resonator

soundboard and cavity resonator both are nouns.

Word	Noun	Adjective	Verb	Adverb
soundboard	Yes	No	No	No
cavity resonator	Yes	No	No	No

As nouns, cavity resonator is a hypernym of soundboard; that is, cavity resonator is a word with a broader meaning than soundboard:

soundboard: (music) resonator consisting of a thin board whose vibrations reinforce the sound of the instrument
cavity resonator: a hollow chamber whose dimensions allow the resonant oscillation of electromagnetic or acoustic waves

Other hypernyms of soundboard include resonating chamber, resonator.

soundboard (noun)	cavity resonator (noun)
(music) resonator consisting of a thin board whose vibrations reinforce the sound of the instrument	a hollow chamber whose dimensions allow the resonant oscillation of electromagnetic or acoustic waves