party favor vs favour

party favor and favour both are nouns.

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

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

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

Other synonyms of party favor include favor, party favour.

party favor (noun)	favour (noun)
souvenir consisting of a small gift given to a guest at a party	an act of gracious kindness
	souvenir consisting of a small gift given to a guest at a party
	an advantage to the benefit of someone or something
	an inclination to approve
	a feeling of favorable regard