The trunk or cargo liner is the space in the car, which is provided for transporting cargo. In general, it is in the rear, and some types of vehicles have it too. The trunks are usually made of needled composite materials and high-quality combination models sometimes from the tufted carpet. In trunks, which are not separated by sheet metal from the passenger compartment, trunk, the parts meet the VDA-fire standards for interior parts (firing rate not exceeding 10 cm / min). The volume of the trunk is usually expressed in liters, which is used to determine the volume of the VDA with a process standard of blocks (50 mm × 200 mm × 100 mm). The method for loading of the boot with these measuring blocks is described in the DIN 70020-1 and ISO 3832^nd.

In a closed trunk is understood one which is from the passenger compartment, while the open trunk is accessible by removing a cover or folding down the rear bench seat. In a medium sized car is about 250-500 liters of load volume. Many car models can be expanded to many times by folding down the rear seat, the load volume. Thus, the load length increases cm to about 50. In a cluster is then usually a load length of up to two meters.

The trunk can be used in addition to the transportation of luggage for many other purposes such as to accommodate a spare wheel, an auxiliary or gas tanks with gas-powered vehicles, car stereo, or it can be mounted another row of seats (for vans).