A wind tunnel is a room or passage through which air can be made to flow at controlled speeds. Wind tunnels are used to test new equipment or machinery, especially cars and aeroplanes.
wind tunnel in British English
(wɪnd)
noun
a chamber for testing the aerodynamic properties of aircraft, aerofoils, etc, in which a current of air can be maintained at a constant velocity
wind tunnel in American English
US
a tunnel-like chamber through which air is forced and in which airplanes, motor vehicles, etc., or their scale models, are tested to determine the effects of wind pressure