Plain English Meaning

A partial flap setting — not all the way up, not all the way down — somewhere in the middle of the flap's range of travel.

Full Definition

An intermediate flap setting between fully retracted (flaps up) and fully extended (flaps down), commonly used during approach, takeoff, or maneuvering to provide additional lift without the full drag penalty of a fully deployed flap.

Context Anchor

Seen in aircraft procedures, performance discussions, and flap-position descriptions when a partial flap setting is being used.

Derivation

A combination of 'mid' (middle) and 'flap' (the hinged trailing-edge surface on a ). The term simply names a position partway through the flap's full travel.