Defensive back

[1][2] Among all the defensive backs, there are two main types, cornerbacks, which play nearer the line of scrimmage and the sideline, whose main role is to cover the opposing team's wide receivers, and the safeties, who play further back near the center of the field, and who act as the last line of defense.

In Canadian football, which has twelve players on the field compared to the eleven of American football, there is an additional position called defensive halfback, which plays like a hybrid between a linebacker and cornerback.

Canadian formations include two cornerbacks, two halfbacks and one safety, for a total of five defensive backs.

Historic notable defensive backs include Hall-of-Famers Dick "Night Train" Lane, Mike Haynes, Ronnie Lott, Troy Polamalu, Deion Sanders, Darrelle Revis, and Ed Reed, among others.

[3] Longtime National Football League executive and renowned former general manager of the Dallas Cowboys, Gil Brandt released a list of the top cornerbacks of all time.