Plain English Meaning
The wheel-shaped handle in front of the pilot that is used to bank the airplane left and right and to raise or lower the nose.
Full Definition
The primary cockpit control used by the pilot to operate the ailerons and elevator. Rotating the wheel left or right deflects the ailerons to roll the airplane, and pushing or pulling the wheel moves the elevator to pitch the airplane nose-down or nose-up.
Context Anchor
Seen in the cockpit and in primary flight-control discussions when learning what push, pull, and turning inputs do.