What is the definition of a bicycle in terms of wheels?

The definition of a bicycle revolves around its basic design and functionality. A bicycle is defined as a vehicle that typically consists of two wheels, which are arranged in a tandem layout. This configuration allows for balance and stability while being propelled primarily by human effort through pedaling. The presence of two wheels is key to its classification as a bicycle, as it distinguishes it from other similar devices such as unicycles, which have one wheel, or tricycles, which have three wheels.

In terms of propulsion, bicycles can be man-powered or may include mechanisms like electric assist; however, traditional bicycles do not rely solely on electric power for movement. Thus, the definition emphasizes the two-wheeled aspect, making it a fundamental characteristic of what constitutes a bicycle.