deadbolts

/D EH1 D B OW0 L T S/
noun
  1. 1

    The part of the lock which is moved when the key is engaged.

  2. 2

    A kind of lock in which the bolt (moving portion) is held in position by the cylinder rather than by a spring and so can not be retracted except by turning the cylinder.

Source: https://en.wiktionary.org/wiki/deadbolt, https://en.wiktionary.org/wiki/deadbolts