Leonardo da Vinci’s multiple-barrel weapon design is commonly called an organ gun.
The design arranged many small cannons in rows or fan-shaped groups. The nickname comes from the visual resemblance between the barrels and the pipes of a musical organ. By placing several guns together, Leonardo sought to increase the volume of fire and reduce the delay between shots. Some versions were mounted on a wheeled frame so they could be moved and aimed.
The weapon was a proposed artillery system, not a modern machine gun. Its barrels still required separate loading and firing, and Renaissance gunpowder technology imposed major limits on speed, accuracy, and safety. The design therefore belongs to the history of volley weapons rather than fully automatic firearms.
Leonardo’s drawings show his continuing interest in combining many simple mechanisms into one battlefield device. Whether a particular version was built or used is uncertain, but the concept is clearly represented in his military-engineering work.