zone-circlehttp://www.oed.com/dictionary/zone-circle_n%3Ftab%3Dmeaning_and_usezone-circle, n.
First published 1921; not fully revised

zone-circlenoun

  1. 1878–
    1. 1878
      The poles of all the faces in the same zone will lie in the same zone circle.
      H. P. Gurney, Crystallography 32

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

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