Source : Webster's Revised Unabridged Dictionary (1913)

Cotillon \Co`til`lon"\ (k[-o]`t[-e]`y[^o]N" or k[-o]`t[-e]l`-;
   277), Cotillion \Co*til"lion\ (k[-o]*t[i^]l"y[u^]n), n. [F.
   cotillon, fr. OF. cote coat, LL. cotta tunic. See {Coat}.]
   1. A brisk dance, performed by eight persons; a quadrille.

   2. A tune which regulates the dance.

   3. A kind of woolen material for women's skirts.

Source : WordNet®

cotillion
     n 1: a ball at which young ladies are presented to society [syn:
          {cotilion}]
     2: a lively dance originating in France in the 18th century
        [syn: {cotilion}]