molting vs moulting

molting and moulting both are nouns.

Word	Noun	Adjective	Verb	Adverb
molting	Yes	No	No	No
moulting	Yes	No	No	No

As nouns, molting and moulting are synonyms defined as:

molting and moulting: periodic shedding of the cuticle in arthropods or the outer skin in reptiles

Other synonyms of molting include ecdysis, molt, moult.

molting (noun)	moulting (noun)
periodic shedding of the cuticle in arthropods or the outer skin in reptiles	periodic shedding of the cuticle in arthropods or the outer skin in reptiles