0 a bicycle that has only one gear (= a device that controls how much power goes to the wheels of a vehicle) and that cannot move unless the pedals are being turned, often used for getting around a city: --
In Boston, New York and London, couriers pioneered the art of riding fixed-wheel bicycles in city traffic.
Riding a "fixie" - fixed-wheel bike - on the hills of San Francisco is impressive.
This fixed-gear bicycle is easy to maintain and ideal for commuters.
Fixed-gear bikes are being ridden all over New York, by messengers, racers, lawyers, accountants and college professors.