undulation vs waveform

undulation and waveform both are nouns.

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

As nouns, waveform is a hyponym of undulation; that is, waveform is a word with a more specific, narrower meaning than undulation:

undulation: (physics) a movement up and down or back and forth
waveform: the shape of a wave illustrated graphically by plotting the values of the period quantity against time

undulation (noun)	waveform (noun)
(physics) a movement up and down or back and forth	the shape of a wave illustrated graphically by plotting the values of the period quantity against time
wavelike motion; a gentle rising and falling in the manner of waves
an undulating curve