marvelously vs marvellously

marvelously and marvellously both are adverbs.

Word	Noun	Adjective	Verb	Adverb
marvelously	No	No	No	Yes
marvellously	No	No	No	Yes

As adverbs, marvelously and marvellously are synonyms defined as:

Other synonyms of marvelously include superbly, terrifically, toppingly, wonderfully, wondrous, wondrously.

marvelously (adverb)	marvellously (adverb)
(used as an intensifier) excellently	(used as an intensifier) excellently