In American football, a nickelback is a cornerback who serves as the fifth defensive back on defense. Like a dimeback, nickelbacks are backup corners (as opposed to the #1 and #2 corners, who are considered starters). Nickelback is usually played by a slightly better cornerback than dimeback and the player must be better at runing defense, as the nickel formation is mainly used as a compromise between run and pass defense formations. United States simply as football, is a competitive team sport that is both fast-paced and strategic. ... Defensive back (DB) is a player in American football whose role is primarily pass coverage; that is, the defensive back will stay near a receiver and try to deflect or intercept any passes thrown to him. ... In American football, a dimeback is a cornerback who serves as the sixth defensive back on defense. ... A Formation in American football refers to the position players line up in before the start of a play from scrimmage. ...