Football a play in which a player grounds the ball behind the player's own goal line when the ball was caused to pass the goal line by an opponent
See touchback in American Heritage Dictionary 4
(tŭchˈbăkˌ)
noun Football
A play in which the defensive team recovers and downs the ball behind its own goal line after the ball has been kicked or passed there by the team on offense. No points are scored, and the ball is put back in play by the recovering team on its own 20-yard line.