zone-defencehttp://www.oed.com/dictionary/zone-defence_n%3Ftab%3Dmeaning_and_usezone defence | zone defense, n.
First published 1986; not fully revised

zone defence | zone defensenoun

American Football and Basketball.
  1. 1927–
    A system of defensive play whereby each player guards an allotted portion of the field of play.
    1. 1927
    2. 1929
      Zone defense, in which each individual is responsible for a certain zone.
      H. C. Carlson, You & Basket Ball vi. 128
    3. 1937
      It is to be noticed in charting these penetrating offensive plays against a zone defense that the setup of the offense is identical with that used in penetrating the man-for-man defense.
      F. C. Allen, Better Basketball xviii. 291
    4. 1970
      Zone defense, a type of pass defense in which each of the three linebackers and four deep backs is assigned to cover a specific area of the field. Zone defense contrasts with man-to-man defense.
      G. Sullivan, Pro Football A to Z 341

Originally published as part of the entry for zone, n.

zone, n. was first published in 1921; not fully revised.