zinc-dusthttp://www.oed.com/dictionary/zinc-dust_n%3Ftab%3Dmeaning_and_usezinc-dust, n.
First published 1921; not fully revised

zinc-dustnoun

  1. 1877–
    Zinc in the form of fine powder (often mixed with zinc oxide and other impurities), obtained by grinding, or in the extraction of zinc from its ores, and used as a deoxidizing agent and as a paint (see zinc-grey n.).
    1. 1877
      Action of Zinc-dust on the Chlorides of Sulphoparabromobenzoic Acid.
      Journal of Chemical Society vol. 32 468

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

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