acoustic wave vs undulation

acoustic wave and undulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
acoustic wave	Yes	No	No	No
undulation	Yes	No	No	No

As nouns, undulation is a hypernym of acoustic wave; that is, undulation is a word with a broader meaning than acoustic wave:

Other hypernyms of acoustic wave include wave.

acoustic wave (noun)	undulation (noun)
(acoustics) a wave that transmits sound	(physics) a movement up and down or back and forth
	wavelike motion; a gentle rising and falling in the manner of waves
	an undulating curve