Wiktionary
n. (context American football English) Any of a few defensive positions in the middle of the defensive line.
Wikipedia
A defensive tackle (DT) is typically the largest and strongest of the defensive players in American football. The defensive tackle typically lines up opposite one of the offensive guards. Depending on a team's individual defensive scheme, a defensive tackle may be called upon to fill several different roles. These roles may include merely holding the point of attack by refusing to be moved or penetrating a certain gap between offensive linemen to break up a play in the opponent's backfield. If a defensive tackle reads a pass play, his primary responsibility is to pursue the quarterback, or simply knock the pass down at the line if it's within arm's reach. Other responsibilities of the defensive tackle may be to pursue the screen pass or drop into coverage in a zone blitz scheme. In a traditional 4–3 defensive set, there is no nose tackle. Instead there is a left and right defensive tackle. Some teams especially in the NFL do have a nose tackle in this scheme, but most of them do not.
Usage examples of "defensive tackle".
Center Raymond Wolsczak and guard Herman Doffman rose to gently box in the little man in stocking feet, lest he get between the runner Hooker and the defensive tackle, Bettee, and wind up in the hospital.
When the play ended a defensive tackle named Dickie Kidd remained on his knees.
It was unlocked and he barreled into the reception chamber like a defensive tackle blitzing a quarterback.
The red stumbled, regained balance, and charged her like an enormous defensive tackle.
That she had not played defensive tackle for the Pittsburgh Steelers, said one of the agents outside her hearing, was that she probably didn't like the untidiness of the locker rooms.