Van: a covered vehicle (a box with wheels!) of any size. The Royal Mail uses vans to deliver Post. Truck: a small vehicle with an open back; sides but no top. Builders use trucks for carrying equipment and materials. Wagon: a large vehicle used for transporting loads long distance. All these definitions are British; I think American definitions are different. We have a word 'lorry,' which is a medium to large vehicle used for carrying heavy loads or large volumes.

thanks all for your help!

a truck is a bigger and much heavier version of a van primarily used for transport of cargo, while a wagon is a 4 wheeled vehicle usually pulled by animals like horses or oxen ....but "wagon" can also be used to refer to a light transport vehicle .. hope that helps ...

They are the types of vehicles, it's better to search for photographs of them, me speaking about them wouldn't help much. A van is something that people hire to move their things from their old house to their new house (usually a white van - a "transit van") - a truck can be different things, "dumper truck" or to "keep on trucking!!" is to keep driving a large "heavy goods vehicle" (HGV) - and a wagon is like a truck, or it could actually be the same vehicle with a different name - I have a feeling (and sorry because feelings don't help much) - but a wagon might be the name for a large truck. Google some pictures :)