The noun 派对 (pàiduì) means "party" in the social gathering sense. It is a loanword from English and is commonly used among younger speakers and in casual contexts. It often appears alongside words like 生日派对 (birthday party) or 派对聚会 (party gathering).
她给自己办了一个生日派对。
tā gěi zìjǐ bàn le yí gè shēngrì pàiduì.
She threw herself a birthday party.
今晚的派对你去不去?
jīn wǎn de pàiduì nǐ qù bú qù?
Are you going to tonight's party or not?
他们在海边开了一个很酷的派对。
tāmen zài hǎibiān kāi le yí gè hěn kù de pàiduì.
They threw a really cool party by the beach.