A pitot tube is used by
aircraft to measure their
approximate velocity. Pitots can be heated to set the incoming air to a
referenced
temperature. The pressure is routed to a
sensor, and the velocity is
calculated. This information can be used as an input to the
flight computer or as a standby in case the more accurate
doppler system goes down in
military aircraft. Modern pitots closely resemble
machine gun barrels in
appearance.
I think this definition was a little after Webster 1913's time.