Plain English Meaning
It is how the pilot tilts the wings left or right, and holds them at the angle they want, by moving the control wheel or stick sideways.
Full Definition
Bank control is the management of the airplane's rotation about its longitudinal axis (the line running from nose to tail) by use of the ailerons to establish or maintain a desired angle of bank relative to the horizon.
Context Anchor
Used in attitude flying when a pilot is to the airplane by to the horizon and .