lock nut

or lock·nut

noun Machinery.

a nut specially constructed to prevent its coming loose, usually having a means of providing extra friction between itself and the screw.
Also called jam nut. a thin supplementary nut screwed down upon a regular nut to prevent its loosening.

Origin of lock nut

First recorded in 1860–65
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for lock nut

  • The lock-nut D holds the screw securely once the pressure is adjusted.

    Practical Lithography|Alfred Seymour