zero-posthttp://www.oed.com/dictionary/zero-post_n%3Ftab%3Dmeaning_and_usezero post, n.
Revised 2018

zero postnoun

  1. 1908–
    A post from which distances along roads or railway lines are measured; cf. zero mark n.
    1. 1908
      The zero posts which formerly stood on the present site of the Marble Arch, and at Hyde-park-corner.
      Daily Chronicle 9 January 3/3
    2. 1924
      Workmen are putting up what is known as the zero post of the Magnolia Route at the intersection of 14th Street and 25th Avenue.
      Daily Herald (Gulfport & Biloxi, Mississippi) 20 October 4/2
    3. 1983
      Railway branch lines have zero posts; there is one at Shipley.
      Country Life 15 September 676/3

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

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