A breech-loading machine gun consisting of a number of barrels fitted together, so arranged that the barrels can be fired simultaneously, or successively, and rapidly.

The mitrailleuse was a manually-fired volley gun developed in France by Major Verchere De Reffye during the 1860s , with the direct support of French Emperor Napoleon III. It was repeatedly used in battle by the French Army during the Franco-Prussian War (1870-1871). It was the first rapid-firing weapon to be deployed as standard equipment by any army in a major conflict.