coffin corner definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
any of the corners of a football field formed by a goal line and side line: punts are sometimes directed to a coffin corner so that the ball will go out of bounds near the opponent's goal line
Origin: radio slang, probably with reference to the grave of the defending team's hopes
coffin corner definition by American Heritage Dictionary
Either corner of the field formed by the sideline and the defending team's goal line. The ball may be deliberately punted out of bounds in this area, thus forcing the receiving team to play very close to its goal line.