The Collaborative International Dictionary of English v.0.48:

Armorer \Ar"mor*er\, n. [OE. armurer, armerer, fr. F. armurter,
   fr. armure armor.]
   1. One who makes or repairs armor or arms.
      [1913 Webster]

   2. Formerly, one who had care of the arms and armor of a
      knight, and who dressed him in armor. --Shak.
      [1913 Webster]

   3. One who has the care of arms and armor, cleans or repairs
      them, etc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

armorer
    n 1: a worker skilled in making armor or arms; "a sword made by
         a famous English armorer" [syn: armorer, armourer]
    2: an enlisted man responsible for the upkeep of small arms and
       machine guns etc. [syn: armorer, armourer, artificer]
    3: a manufacturer of firearms [syn: armorer, armourer]