zinc-filingshttp://www.oed.com/dictionary/zinc-filings_n%3Ftab%3Dmeaning_and_usezinc filings, n.
First published 1921; not fully revised

zinc filingsnoun

  1. 1809–
    1. 1809
      The concrete phosphoric acid, heated with zinc-filings, is decomposed.
      J. Murray, System Chemistry (ed. 2) vol. III. 305

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

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