The Collaborative International Dictionary of English v.0.48:

Armament \Ar"ma*ment\, n. [L. armamenta, pl., utensils, esp. the
   tackle of a ship, fr. armare to arm: cf. LL. armamentum, F.
   armement.]
   1. A body of forces equipped for war; -- used of a land or
      naval force. "The whole united armament of Greece."
      --Glover.
      [1913 Webster]

   2. (Mil. & Nav.) All the cannon and small arms collectively,
      with their equipments, belonging to a ship or a
      fortification.
      [1913 Webster]

   3. Any equipment for resistance.
      [1913 Webster]

WordNet (r) 3.0 (2006):

armament
    n 1: weaponry used by military or naval force
    2: the act of equiping with weapons in preparation for war [syn:
       arming, armament, equipping] [ant: disarmament,
       disarming]