しゅくが祝賀shukuga
1.

A communal gathering or event in which people come together to express joy and celebrate a significant occasion or achievement.

2.

An act of honoring or acknowledging a happy event, often involving festivities and expressions of goodwill among participants.

しゅくがかい祝賀会shukugakai
1.

An event or gathering held to honor and commemorate a special occasion or achievement, often characterized by festivities and social interactions.

2.

A formal ceremony or reception organized to express joy and congratulations, typically involving food, drinks, and speeches.

Example:

その祝賀会で、彼は自分の親戚に私を紹介した。