Plain English Meaning

How far the wings are tilted away from level, measured in degrees. A wings-level airplane has zero bank; a steeply banked airplane has its wings tilted well off horizontal.

Full Definition

The angle between an airplane's lateral axis (wingtip to wingtip) and the horizon, measured in degrees, when the airplane is rolled to one side during a turn or maneuver.

Context Anchor

You see this term when learning and practicing turns, especially level turns, where the airplane must be tilted to turn while holding altitude.

Derivation

Bank' comes from the old sense of a sloped or tilted (like a banked road or river bank). When an airplane rolls, its wings form a sloped surface to the horizon -- so pilots speak of the airplane being 'banked.'