Shotshells / shot cartridges
A shotshell is a cartridge, which is specifically designed for the use in shotguns.
Contrary to rifle cartridges, not a single bullet is fired, but many little shot pellets.
The size and number of the shot is adjusted to the intended purpose.
A special form of shotgun shells is a shotgun slug.
These make it possible to fire a single bullet from shotgun barrels.