A cornerback is a position on defense in American football. Corners can rush the passer, intercept balls, tackle, and deflect passes. Their main job is to stop the opponent's receivers from making a catch. Cornerbacks usually line up on the edges, or sides, of the defensive line opposite their opponent's receivers. In "zone defense", corners are assigned to a specific area of the field, in which they cannot let anyone make a catch. In "man defense", corners cover one player and try to stop them from catching a ball.