Small, single rider vehicle that weighs from 300 - 600+ pounds. Meant to explore parts of this world that no Jeep, Land Rover, or Truck were ever meant to go. They come in wide varieties (auto, manual, semi-manual) (2-stroke, 4-stroke) (sport, utility).
Some brands are Polaris, Kawasaki, Honda, Yamaha, Arctic Cat, Bombardier, etc.
Tommy got his four-wheeler stuck in a creek! I'll go get my four wheeler to pull it out.