BALLISTA, or BALISTA, a military engine used by the ancients for discharging darts, javelins, and stones. The name is derived from the Greek word βαλλειν, to throw. It would appear that the projectile force of these machines, in their several kinds, was derived from the torsion of ropes by means of a lever. Their power was very great, and indeed they may be said to have answered, in some degree, the purposes of modern artillery. The balista originally differed from the catapulta, which was used for discharging darts; but they are confounded by writers subsequent to the time of Julius Cæsar.