What is "rebounding lock"

Rebound \Re*bound"\ (r[-e]*bound"), v. i. [Pref. re- + bound: cf. F. rebondir.]

1. To spring back; to start back; to be sent back or reverberated by elastic force on collision with another body; as, a rebounding echo.

   Bodies which are absolutely hard, or so soft as to be void of elasticity, will not rebound from one another.
   --Sir I. Newton.

2. To give back an echo. [R.]
   --T. Warton.

3. To bound again or repeatedly, as a horse.
   --Pope.

4. to recover, as from sickness, psychological shock, or disappointment.

   Rebounding lock (Firearms), one in which the hammer rebounds to half cock after striking the cap or primer.

vb. (context firearms English) A lock in which the hammer rebounds to half cock after striking the cap or primer.