Plain English Meaning

Quick, unwanted side-to-side movements of the airplane while taxiing — the nose darts left or right when you didn't mean it to.

Full Definition

Sudden, unintended sideways deviations of the airplane from its intended taxi path, typically caused by uneven braking, crosswind effects, excessive power application, or abrupt rudder or nosewheel steering inputs.

Context Anchor

You will see this term in taxiing discussions, especially when learning to keep the airplane moving straight and under control on the ground.

Derivation

From Old English 'sweorfan,' meaning to turn aside or rub. The everyday sense — a car swerving to avoid something — carries straight into aviation: an unplanned sideways turn away from the intended path.