quadrille

/kwɑˈdrɪl/

Other forms: quadrilles

You may not have danced a quadrille, a complicated dance that includes at least four pairs of dancers — because it reached its height of popularity in the mid-1800s.

Your language instincts probably push you towards the idea of squareness or fourdom when you see quad, and there are good reasons for both tendencies: the Latin quattuor lies behind many English words incorporating notions of "four" and "four corners." A quadrille, originally a card game for four people, morphed eventually to also mean a square dance for four couples.

Definitions of quadrille

1. noun

   a square dance of 5 or more figures for 4 or more couples
   types:

   lancers

   a quadrille for 8 or 16 couples

   type of:

   square dance, square dancing

   American country dancing in which couples form squares
2. noun

   music for dancing the quadrille
   type of:

   dance music

   music to dance to