noun
A formal social event for dancing, such as a ball or dance party.
彼女は舞踏会で美しいドレスを着ていた。
She wore a beautiful dress at the ball.
舞踏会は夜遅くまで続いた。
The dance continued until late at night.
Compound of 舞踏 (dancing) and 会 (gathering). The exact historical derivation is uncertain, but the word has been used since the Meiji era for Western-style balls.