ELI5: Explain Like I'm 5

Trailer (vehicle)

A trailer is a vehicle that is pulled behind a car, truck or van. It's like a box on wheels. It can be used to store and transport things like furniture, sports equipment, camping gear or supplies for your job. It has four wheels and a long metal tongue that connects it to the car, truck or van. When the car, truck or van moves forward, the trailer follows.