A tricycle (often abbreviated to trike) is a three-wheeled vehicle.
Tricycles generally follow one of two layouts:
Not all trikes fall into one of these two classes. For example, some early pedal tricycles used two wheels in tandem on one side and a larger driving wheel on the other. It is common for tricycles to have front and rear wheels of different sizes.
The word tricycle has been in use since the early 19th century. The first recorded usage is in 1828, signifying a "three-wheeled horse-drawn carriage." Tricycles have evolved to include various forms of propulsion including pedals, steam and internal combustion engines. The abbreviation trike has been in use since 1883.