D defs.my
Entry 1 sense Webster, 1913

Doornail

/(dōr"nāl`)/ · Door·nail · IPA /dˈɔrnˌeɪl/
01 n. The nail or knob on which in ancient doors the knocker struck; -- hence the old saying, “As dead as a doornail.”
  1. 1.
    The nail or knob on which in ancient doors the knocker struck; -- hence the old saying, “As dead as a doornail.”