What does the word brace mean?

Usage examples for brace

  1. " In our army the fear prevailed that the Tsar would never brace himself up to the decision to make war. – The Coming Conquest of England by August Niemann
  2. Brace up, Patty girl, don't let this thing floor you. – Patty's Suitors by Carolyn Wells
  3. The momentary stir gave her a chance to brace herself. – The Amazing Interlude by Mary Roberts Rinehart