(American football) Any of a few defensive positions in the middle of the defensive line.

(ice hockey) The ice between a team's own blue line and its end board.

plural of defensive zone

(soccer) A midfield player who specialises more in defensive duties.

(American football, Canadian football) 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.

(Canadian football) A defensive back whose primary jobs are to cover the slotback on passing plays and prevent running plays from going to the outside.

(computing) The practice of planning for contingencies in the design stage of a project so as to make the misuse of the software impossible, or to minimise the negative consequences.

plural of defensive design

(programming) A form of defensive design aiming to ensure the continuing functioning of a piece of software in spite of unforeseeable usage of it.

plural of defensive back