fluctuation vs undulation

fluctuation and undulation both are nouns.

Word	Noun	Adjective	Verb	Adverb
fluctuation	Yes	No	No	No
undulation	Yes	No	No	No

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

Other hypernyms of fluctuation include wave.

fluctuation (noun)	undulation (noun)
the quality of being unsteady and subject to changes	(physics) a movement up and down or back and forth
an instance of change; the rate or magnitude of change	wavelike motion; a gentle rising and falling in the manner of waves
a wave motion	an undulating curve