Leonardo da Vinci designed an organ gun, a multi-barrel weapon arranged to fire many guns in succession.
His drawings show rows of small cannon barrels mounted on a frame. The arrangement resembled the pipes of a musical organ, which explains the name. Some versions used a platform that could be raised or angled, allowing a broad volley against a target.
The concept belongs to Renaissance military engineering and was intended to increase the number of shots delivered at once. It was not a machine gun in the modern sense: it required manual loading and did not use automatic ammunition feeding.
Leonardo also designed other weapons, including giant crossbows and an armored vehicle. Those machines should not be treated as alternative names for the organ gun.