zinc-greyhttp://www.oed.com/dictionary/zinc-grey_n%3Ftab%3Dmeaning_and_usezinc-grey | zinc-gray, n.
First published 1921; not fully revised

zinc-grey | zinc-graynoun

  1. 1881–
    a. Zinc-dust obtained by grinding in oil, used as a preservative paint for ironwork; b. a colour resembling that of zinc.
    1. 1881
      Zinc-gray, see Zinc-dust.
      Transactions of American Institute of Mining Engineers 1880–1 vol. 9 192
    2. 1900
      Zinc grey is very much worn.
      Westminster Gazette 11 January 3/2

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

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