A tractor is a vehicle that's used on a farm or work site, often to pull a trailer or other equipment. A farmer might use a tractor to pull a plow through her corn field before planting.
Tractors typically have two large wheels in back, and smaller wheels in front. The cab of a tractor, where the driver sits, is sometimes open at the sides. When tractors were first used in farm work, they replaced horses and other large animals once commonly used to pull plows and move heavy equipment. The original meaning of tractor was "something that pulls," while in Modern Latin it means "that which draws," from trahere, "to pull or draw."