Plain English Meaning

The fixed upright fin at the back of the airplane. It keeps the nose pointed straight into the relative wind, much like the feathers on an arrow keep the arrow flying straight.

Full Definition

The fixed, upright airfoil-shaped surface mounted on the tail of an airplane that provides directional (yaw-axis) stability by keeping the nose aligned with the direction of flight. The rudder is hinged to its trailing edge.

Context Anchor

Seen during preflight inspection, in airplane parts diagrams, and when learning how the tail helps control left- movement of the nose.