brassard(n = noun.artifact) - armor plate that protects the arm;
is a kind of armor plate, armor plating, armour plate, plate armor, plate armour
is a part of body armor, body armour, cataphract, coat of mail, suit of armor, suit of armour

   an armor plate that protects the arm. [WordNet 1.5]

brassard, n. a band worn on the sleeve, esp. with a uniform.

Etymology:
F bras arm + -ARD