'locknut' definitions:

Definition of 'locknut'

From: WordNet
noun
Supplementary nut that is screwed down on a primary nut to prevent it from loosening [syn: locknut, safety nut]

Definition of 'locknut'

From: GCIDE
  • locknut \locknut\, lock nut \lock nut\n. a supplementary nut that is screwed down on a primary nut to prevent it from loosening; a check nut. [WordNet 1.5]