Definition
The use of the ailerons to control the airplane's rotation about its longitudinal axis — the axis running nose to tail — to keep the wings level or to bank the airplane left or right.
Plain English
Roll control is how the pilot raises one wing and lowers the other, or keeps both wings level, using the control wheel or stick.
Context Anchor
Seen in stall recovery because, near a stall, the airplane may not respond normally when the pilot tries to keep the wings level.
Derivation
Roll' describes the airplane rotating side-to-side around its long axis, like a log rolling. 'Control' here means the pilot's ability to command that motion — in this case through the ailerons.
Why Pilots Care
Loss of roll control in a stall can allow an unintentional bank to develop into a spin.
Intuition Check
Roll control does not mean steering the airplane like a car. It means controlling whether the wings stay level or tilt left or right.
Example Sentence 1
As the airplane approached the stall, the instructor reminded the student to use rudder, not aileron, until full roll control was restored.
Example Sentence 2
The pilot applied gentle roll control to establish the desired bank angle for the turn.