Plain English Meaning

Panels on the back edge of each wing that the pilot can lower to help the airplane fly slower and come down more steeply for landing without stalling.

Full Definition

Hinged, movable surfaces on the trailing edge of the wing, near the fuselage, that can be lowered (extended) to increase the wing's lift and drag at slower airspeeds. Flaps allow the airplane to fly safely at lower speeds, which is useful for takeoff and especially for landing, where they enable a steeper descent path and a slower touchdown.

Context Anchor

You will see flaps on the cockpit flap control, on landing and after-landing checklists, and in that tell you when to extend or them.