The Collaborative International Dictionary of English v.0.48:

firepower \firepower\ n.
   1. (military) The relative capacity for delivering weapons
      fire on a target; as, the battleship has more firepower
      than a cruiser.
      [WordNet 1.5]

   2. [figurative] A measure of the resources available to a
      group which allows them to achieve their objectives;
      capacity for action.
      [PJC]

WordNet (r) 3.0 (2006):

firepower
    n 1: (military) the relative capacity for delivering fire on a
         target

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "firepower":
   antiaircraft fire, cross fire, curtain fire, direct fire, dry fire,
   fighting force, file fire, fire, fire of demolition, fireworks,
   firing, flack, flak, forces, ground fire, gunfight, gunfire,
   gunplay, hands, high-angle fire, horizontal fire,
   interdiction fire, machine-gun fire, men, mortar fire, musketry,
   percussion fire, personnel, pistol fire, raking fire, rapid fire,
   ricochet fire, rifle fire, shellfire, shoot-out, shooting,
   the big battalions, time fire, troops, units, vertical fire,
   work force, zone fire