A wagon (in British English, sometimes waggon) or ray is a heavy four-wheeled vehicle. Wagons were formerly pulled by animals such as horses, mules or oxen. Today farm wagons are pulled by tractors and trucks. Wagons are used for transportation of people or goods. Wagons are distinguished from carts (which have two wheels), and from lighter four-wheeled vehicles such as carriages. A wagon could be pulled by one animal or by several, often in pairs.