party favour vs party favor

party favour and party favor both are nouns.

Word	Noun	Adjective	Verb	Adverb
party favour	Yes	No	No	No
party favor	Yes	No	No	No

As nouns, party favour and party favor are synonyms defined as:

party favour and party favor: souvenir consisting of a small gift given to a guest at a party

Other synonyms of party favour include favor, favour.

party favour (noun)	party favor (noun)
souvenir consisting of a small gift given to a guest at a party	souvenir consisting of a small gift given to a guest at a party