What is the catch in a gunlock by which the hammer is held cocked or half cocked. Sear spring, the spring which causes the sear to catch in the notches by which the hammer is held called?

sear — The catch in a gunlock by which the hammer is held cocked or half cocked. Sear spring, the spring which causes the sear to catch in the notches by which the hammer is held. (Webster's 1913.)