Source : Webster's Revised Unabridged Dictionary (1913)

Vambrace \Vam"brace\, n. [See {Vantbrass}.] (Anc. Armor)
   The piece designed to protect the arm from the elbow to the
   wrist.

Source : WordNet®

vambrace
     n : cannon of plate armor protecting the forearm [syn: {lower
         cannon}]