A salvo is the simultaneous discharge of artillery or firearms including the firing of guns either to hit a target or to perform a salute.
Troops armed with muzzleloaders required time in which to refill their arms with gun powder and shot. Gun drills were designed to enable an almost continuous rain of fire on the enemy by lining troops into ranks, allowing one rank to fire a salvo, or volley, while the other ranks prepared their guns for firing.
The term is commonly used to describe the firing of broadsides by warships, especially battleships. During fleet engagements in the days of sail, from 17th century until the 19th century, ships of the line were maneuvered with the objective of bringing the greatest possible number of cannon to bear on the enemy and to discharge them in a salvo, causing enough damage and confusion as to allow time for the cannon to be swabbed out and reloaded.
