A round shot is an artillery projectile with a spherical shape, generally used in a cannon. The first round shots used in cannons were made of stone, and at the end of the XVth century they were replaced with cast iron round shots. The use of cast iron made it possible to get round shots with higher penetration force at the impact.

If the traditional round shot, that is to say the full and spherical one mainly used to aim at the hull and the sailing of ships, was the most used by sailors, other kinds of round shot existed, with other functions.

As a matter of fact, combined round shots were also used, that is to say two or four round shots gathered and tied up with chains. This kind of round shots was mainly used against ships' riggings or against the crew.

The simple round shot could be used in other ways as well. It could be highly warmed up in order to create a conflagration when hitting the target, or be stuffed with explosive materials.