Plain English Meaning

Small locks inside the wheel well that grab the landing gear once it's tucked up and hold it there until the pilot commands it down again.

Full Definition

Mechanical latches in a retractable landing gear system that hold each gear leg securely in the up (retracted) position after retraction, preventing the gear from falling out of its wheel well due to gravity, airloads, or loss of hydraulic pressure.

Context Anchor

Encountered in retractable-gear airplanes, especially in landing gear system descriptions and emergency gear extension procedures.

Derivation

A of 'up' (the ) and 'lock' (a device that secures something in place). The name describes exactly what it does: locks the gear up.