zenith-pointhttp://www.oed.com/dictionary/zenith-point_n%3Ftab%3Dmeaning_and_usezenith point, n.
Revised 2018

zenith pointnoun

  1. 1585–
    The point on the celestial sphere directly overhead at a particular location; = zenith n. A.1a.
    1. 1585
      The Azimuthes..are those which are drawne cutting all the almicantares meeting altogither at one point..: which point I call the zenith point of the reete.
      J. Blagrave, Math. Iewel ii. xvi.
    2. a1652
      Only in North Declinations the Equinoctiall goes nearer the Zenith point, in South it goes further of.
      S. Foster, Elliptical Horologiography (1654) 63
    3. 1829
      The zenith sector..can be used only on the meridian; and its measures are referred to the zenith point of the place of observation.
      W. Pearson, Practical Astronomy vol. II. 531
    4. 1950
      From the known positions of the star images in the celestial sphere, the co-ordinates of the zenith point may be computed.
      Technical Data Digest January 7/3
    5. 2011
      The observer..is at O and the plane containing the circle NESW is again the horizon with Z the zenith point.
      P. Duffet-Smith & J. Zwart, Pract. Astron. with Calculator (ed. 4) xviii. 35

Originally published as part of the entry for zenith, n. & adj.

zenith, n. & adj. was revised in June 2018.