An ATV is a small open vehicle built to ride over rough ground where there are no proper roads — mud, sand, hills, farm tracks. It has one seat, no roof, and three or four large wheels. The letters stand for all-terrain vehicle. In some places people also call the four-wheel kind a quad or a four-wheeler. It is not a car and not a motorbike, though it sits somewhere between. Though actually, people stretch ATV to almost any off-road buggy; the strict picture is that little one-person machine. The same letters can mean other things in other worlds (a TV station, for example), but this entry is the vehicle.