Why is the passengers seat called shotgun in a car?

The term "shotgun" for the passenger seat in a car comes from the days of the Wild West in the United States. Stagecoaches often carried armed passengers to protect against bandits. The passenger sitting next to the driver, in the most exposed position, would typically carry a shotgun to defend against attacks. This seat became known as the "shotgun seat," and the name stuck even after cars replaced stagecoaches.