Where is it defined that a flamethrower needs to use a liquid or gel? Wikipedia says: A flamethrower is a mechanical incendiary device designed to project a l

Where is it defined that a flamethrower needs to use a liquid or gel? Wikipedia says: A flamethrower is a mechanical incendiary device designed to project a long, controllable stream of fire. They were first used by the Greeks in the 1st century AD...Some flamethrowers project a stream of ignited flammable liquid while some project a long gas flame.