Wiktionary
n. A full-sized cargo van that is sent to third-party companies to be outfitted with various luxuries for road trips and camping.
Wikipedia
A conversion van is a full-sized cargo van that is sent to third-party companies to be outfitted with various luxuries for road trips and camping. It can also mean a full-size passenger van in which the rear seating have been rearranged for taxis, school buses, shuttle buses, and limo purposes in place of a family van. Other conversions include bespoke fitting services to be undertaken to make the load area of light commercial vehicles suitable for industrial work. This includes various things such as racking systems for the storage of tools and goods so they can be kept safe and utilise the full storage capability of the vehicle.
Usage examples of "conversion van".
Derek could see it now as some pimple-faced, leather jacketed puberty-bound punk leered at his daughter in his psychedelic conversion van, complete with a mattress in the back.