noun Date: circa 1864 a nut screwed down hard on another to prevent it from slacking back, a nut so constructed that it locks itself when screwed tight against another part
LOCKNUT
Meaning of LOCKNUT in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012