Real Dictionary

wind tunnel
countable noun: 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 American English
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
noun: a tubular chamber or structure in which a steady current of air can be maintained at a controlled velocity, equipped with devices for measuring and recording forces and moments on scale models of complete aircraft or of their parts or, sometimes, on full-

wind tunnel in British English
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