A campervan is like a big car or a small house that you can drive around and sleep in. Imagine a house that is built inside a car!
It has a bed to sleep in, a small kitchen with a sink, stove, and fridge to cook and store food, and sometimes even a bathroom with a shower and a toilet. Everything is small and compact, and a lot of things have more than one use.
You can take a campervan with you on a trip, so you don't have to sleep in a hotel or a tent. You can explore lots of different places and have all your things with you. It's like having a little home on wheels!