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