DictionaryprimerAmmunition igniter
noun

primer

A small explosive cap that ignites ammunition.

The firing pin strikes the primer at the cartridge's base.

Etymology

Primer names something that primes or prepares. In ammunition, the small initial charge starts the ignition that sets off the main propellant.

More examples

  • A faulty primer can keep a cartridge from firing.
  • The technician checks the primers for signs of corrosion.
  • This primer shows a dent from the firing pin.

Forms

primer · primers

prime verb — Prepare a firearm for firing.

Similar words

cap
Often refers specifically to a percussion cap on older firearms.
igniter
Broader term for devices that start combustion, not just ammunition.