In gridiron football, defensive backs, also called the secondary, are the players on the defensive side of the ball who play farthest back from the line of scrimmage. Wikipedia

A position in American football and Canadian football Wikipedia Disambiguation

Position in American football and Canadian football Wikidata

Collective term for the defensive players who are in position farthest from the ball at the start of a play and whose principal responsibility is to defend against passes. Includes cornerbacks and safeties in both codes, and defensive halfbacks in the Canadian game. Wiktionary