A bicycle , also called a pedal cycle , bike , push-bike or cycle , is a human-powered or motor-assisted , pedal-driven , single-track vehicle , with two wheels attached to a frame , one behind the other.
A bicycle rider is called a cyclist, or bicyclist. Bicycles were introduced in the 19th century in Europe. By the early 21st century there were more than 1 billion bicycles.
They also provide a popular form of recreation , and have been adapted for use as children's toys. Bicycles are used for fitness , military and police applications, courier services , bicycle racing , and artistic cycling. The basic shape and configuration of a typical upright or "safety" bicycle , has changed little since the first chain-driven model was developed around These have allowed for a proliferation of specialized designs for many types of cycling.
In the 21st century, electric bicycles have become popular. The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings , pneumatic tires , chain-driven sprockets , and tension-spoked wheels.
Other words for bicycle include "bike", [ 12 ] "pushbike", [ 13 ] "pedal cycle", [ 14 ] or "cycle". Although bike and cycle are used interchangeably to refer mostly to two types of two-wheelers, the terms still vary across the world. The " dandy horse ", [ 18 ] also called Draisienne or Laufmaschine "running machine" , was the first human means of transport to use only two wheels in tandem and was invented by the German Baron Karl von Drais.
