1. See wagon boss.
2. Also,wag'on•mas"ter.a person hired or chosen to lead and guide a caravan of recreational vehicles, as campers, on a trip.
3. Facetious.any leader, chief, commander, or the like: the wagon master of the bill now before Congress.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.