Mules are slightly smaller than their horse parent, and when they grow they share traits of both a donkey (the long ears), and the horse (color, tail, etc.). A Mule in the grass.
For example, a 2014 Ford F-150 is considered a half ton truck but most variants can carry a lot more than 1,000 pounds in the bed. Since these terms are probably not going away any time soon, it's best just to think of them as smaller, mediumest, and more than medium.. (Pause for laughter).
Utilized as a Pickup, instead of a Semi Truck; usually as a 1 ton or a 2 ton Pickup; trailer attached to it; not as heavy or long; usually from 20 to 40 feet long on those trailers. Most weight they can haul is between 12 and 20,000 pounds max.