bi·cy·cle 
(b
īs
ĭk
′əl, -s
ĭ-k
əl, -s
ī′k
əl)
n.1. A vehicle consisting of a light frame mounted on two typically wire-spoked wheels one behind the other and usually having a seat, handlebars for steering, brakes, and two pedals by which it is driven.
2. An exercise bicycle.
intr.v. bi·cy·cled,
bi·cy·cling,
bi·cy·cles To ride or travel on a bicycle.
[Probably BI-1 + -cycle (on the model of TRICYCLE, three-wheeled coach).]
bicy·cler (-klər), bicy·clist (-klĭst) n.