party favor vs party favour

party favor and party favour both are nouns.

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

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

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

Other synonyms of party favor include favor, favour.

party favor (noun)	party favour (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