The Collaborative International Dictionary of English v.0.48:
lancers \lancers\ n. 1. A set of quadrilles for 8 or 16 couples. [WordNet sense 1] [Written also lanciers.] [WordNet 1.5] 2. Music appropriate for a set of lancers[1]. [PJC]WordNet (r) 3.0 (2006):
lancers n 1: a quadrille for 8 or 16 couples