Lethal weapon: defined as an instrument capable of causing serious injury or death, based on its use and capability. The term lethal weapon denotes an instrument capable of causing serious bodily injury or death, determined by its inherent capability and manner of use; firearms are barreled weapons able to discharge a shot, and devices like signal pistols with explosive or incendiary cartridges are treated as lethal when they can produce more than trivial injury likely to cause death.