undulation vs wave form

undulation and wave form both are nouns.

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

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

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

undulation (noun)	wave form (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