uplock

up- +‎ lock

uplock (plural uplocks)

1. (aviation) A mechanism that secures an aircraft's landing gear in the retracted position, helping to prevent an uncommanded gear deployment during flight.
   • 1986 March 29, National Transportation Safety Board, “1.12 Wreckage and Impact Information”, in Aircraft Accident Report: China Airlines Boeing 747-SP, N4522V, 300 Nautical Miles Northwest of San Francisco, California, February 19, 1985‎, archived from the original on 10 July 2022, pages 12–13:

     The left and right wing landing gear uplock assemblies had separated from their attachment points on the fuselage structure. The interior skin and associated ribs on the left and right wing gear inboard doors were damaged in the vicinity of their striker plates and the striker plates also were damaged. The doors were damaged in the area where the tires are located when the gears are retracted.

     The left and right body landing gear uplock hooks were found in the locked-up position, but the fasteners of their uplock support bracket assemblies had failed at the attach points to the fuselage bulkhead.

uplock (third-person singular simple present uplocks, present participle uplocking, simple past and past participle uplocked)

1. (obsolete) To lock up.

• lock up, lock-up, lockup