lock nut

or locknut

noun

, Machinery.

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

Word History and Origins

Origin of lock nut¹

First recorded in 1860–65

Example Sentences

When this adjustment is secured the lock nut is screwed in place so the needle valve will keep the adjustment.

From Project Gutenberg

A lock nut (H), which has corresponding projections (IJ) is slipped over the post as shown at , and is given a quarter turn.

From Project Gutenberg

Then a coupling is cut while screwed on a pipe, so that a lock nut about 1⁄2 inch wide is made.

From Project Gutenberg

A lock nut, O, should be provided for this screw so that it will remain in adjustment.

From Project Gutenberg

The second nut is technically known as a “jam nut,” or “lock nut.”

From Project Gutenberg