lawn party vs garden party

lawn party and garden party both are nouns.

Word	Noun	Adjective	Verb	Adverb
lawn party	Yes	No	No	No
garden party	Yes	No	No	No

As nouns, lawn party and garden party are synonyms defined as:

lawn party and garden party: a party of people assembled for social interaction out of doors

Other synonyms of lawn party include fete champetre.

lawn party (noun)	garden party (noun)
a party of people assembled for social interaction out of doors	a party of people assembled for social interaction out of doors