[ kə'tɪljən ]
■ noun
1》 an 18th-century French dance based on the contredanse.
↘ US a quadrille.
2》 US a formal ball, especially one at which debutantes are presented.
Origin
C18: from Fr. cotillon , lit. 'petticoat dance', dimin. of cotte , from OFr. cote .