Meaning of arrière-ban

ar•ri•ère-ban

Pronunciation: (ar'ē-er"ban' Fr. a&wdspcryer&wdspcbän'), [key]
— pl. -bans
  1. a group of vassals who owed military service, esp. to French kings.
  2. the summoning by a medieval ruler of all vassals and free men for military service.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.