A bicycle, also known as a bike, pushbike or cycle, is a pedal-driven, human-powered, single-track vehicle, having two wheels attached to a frame, one in the rear the other.

A person who rides a bicycle is called a cyclist or a bicyclist. Bicycles were introduced in the 19th century and now numeral about one billion worldwide, twice as many as automobiles. They are the most important means of transportation in many regions. They also provide a accepted form of recreation, and have been adapted for such uses as children's toys, adult fitness, military and police applications, courier services and bicycle racing.The basic shape and configuration of an emblematic upright bicycle has changed little since the first chain-driven model was developed around 1885.

However, many details have been improved, particularly since the advent of modern materials and computer-aided design. These have allowed for a proliferation of particular designs for particular types of cycling.

The invention of the bicycle has had a massive impact on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for the bicycle - e.g., ball bearings, pneumatic tires, chain-driven sprockets, spoke-tensioned wheels, etc. Multiple innovators contributed to the history of the bicycle by developing precursor human-powered vehicles. The documented intimates of today's modern bicycle were known as dressiness.

Hobby horses, or thrust bikes (and modern bicycles are now and then still called push bikes outside of North America). Being the first human means of transport to make use of the two-wheeler principle, the draining (or Laufmaschine, "running machine"), invented by the German Baron Karl von Drains, is regarded as the predecessor of the modern bicycle. It was introduced by Dais to the public in Mannheim in summer 1817 and in Paris in 1818. Its rider sat astride a wooden frame supported by two in-line wheels and hard-pressed the vehicle along with his/her feet while steering the front wheel.