traveling wave vs travelling wave

traveling wave and travelling wave both are nouns.

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

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

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

traveling wave (noun)	travelling 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