noun
mobile showroom; display van; retail truck
A vehicle fitted with facilities for displaying or selling goods, often used for promotional tours or temporary retail.
wasei-eigo (Japanese-coined English), from caravan car
新製品を紹介するために、キャラバンカーが全国を回った。
A mobile showroom toured the country to introduce the new product.
あのキャラバンカーは中で試着もできるらしい。
I heard you can even try on clothes inside that display van.
Wasei-eigo from English 'caravan' + 'car'. The term is not used in English with this meaning.