The Collaborative International Dictionary of English v.0.48:

Orgue \Orgue\, n. [F., fr. L. organum organ, Gr. ?. See
   Organ.] (Mil.)
   (a) Any one of a number of long, thick pieces of timber,
       pointed and shod with iron, and suspended, each by a
       separate rope, over a gateway, to be let down in case of
       attack.
   (b) A piece of ordnance, consisting of a number of musket
       barrels arranged so that a match or train may connect
       with all their touchholes, and a discharge be secured
       almost or quite simultaneously.
       [1913 Webster]