Source : Webster's Revised Unabridged Dictionary (1913)

Ordnance \Ord"nance\, n. [From OE. ordenance, referring orig. to
   the bore or size of the cannon. See {Ordinance}.]
   Heavy weapons of warfare; cannon, or great guns, mortars, and
   howitzers; artillery; sometimes, a general term for all
   weapons and appliances used in war.

         All the battlements their ordnance fire. --Shak.

         Then you may hear afar off the awful roar of his [Rufus
         Choate's] rifled ordnance.               --E. Ererett.

   {Ordnance survey}, the official survey of Great Britain and
      Ireland, conducted by the ordnance department.

Source : WordNet®

ordnance
     n 1: military supplies [syn: {munitions}, {ordnance stores}]
     2: large but transportable armament [syn: {artillery}, {heavy
        weapon}, {gun}]