What does the word countersign mean?

Usage examples for countersign

  1. I, as usual, procured the countersign for that night, so as to be able to get inside the picket post if I should come back in the night, and selecting thirty men, started at five p. – In and Out of Rebel Prisons by Lieut. A. [Alonzo] Cooper
  2. The Ristigouche Salmon Club has its guardians stationed all along the river, and they are quite as inflexible in seeing that their employers keep this law as the famous sentinel was in refusing to let Napoleon pass without the countersign. – Little Rivers A Book Of Essays In Profitable Idleness by Henry van Dyke