Control surface and Flaps

Control surface noun - A device that provides reactive force when in motion relative to the surrounding air; can lift or control a plane in flight.

Flaps and control surface are semantically related. In some cases you can replace term "Flaps" with "Control surface", this terms are similar.

Flaps noun - A movable airfoil that is part of an aircraft wing; used to increase lift or drag.

Control surface and flaps are semantically related. Sometimes you can use "Control surface" instead a noun "Flaps".