travelling wave vs traveling wave

travelling wave and traveling wave both are nouns.

Word	Noun	Adjective	Verb	Adverb
travelling wave	Yes	No	No	No
traveling wave	Yes	No	No	No

As nouns, travelling wave and traveling wave are synonyms defined as:

travelling wave and traveling wave: a wave in which the medium moves in the direction of propagation of the wave

travelling wave (noun)	traveling wave (noun)
a wave in which the medium moves in the direction of propagation of the wave	a wave in which the medium moves in the direction of propagation of the wave