A fire engine or fire truck (also spelled firetruck) is a vehicle, usually a specially-designed or modified truck, that functions as a firefighting apparatus. The primary purposes of a fire engine include transporting firefighters and water to an incident as well as carrying equipment for firefighting operations in a fire drill. Some fire engines have specialized functions, such as wildfire suppression and aircraft rescue and firefighting, and may also carry equipment for technical rescue.
Many fire engines are based on a commercial vehicle chassis that is further upgraded and customized for firefighting requirements. They are generally considered emergency vehicles authorized to be equipped with emergency lights and sirens, as well as communication equipment such as two-way radios and mobile computer technology.
The terms fire engine and fire truck are often used interchangeably to a broad range of vehicles involved in firefighting; however, in some fire departments they refer to separate and specific types of vehicle.