In American football and Canadian football, defensive backs are the players on the defensive team who take positions somewhat back from the line of scrimmage; they are distinguished from the defensive line players, who take positions directly behind the line of scrimmage.

The defensive backs, in turn, generally are classified into several different specialized positions:

• Safety
• Cornerbacks, which include
• nickel backs
• dime backs
• And on rare occasions, a quarter back (not to be confused with the offensive player who throws the ball)