noun
cap
A small explosive charge set off by a strike in a gun.
The percussion cap ignites when the gun's hammer strikes it.
Etymology
Latin cappa named a hood, behind the covering sense of cap. The firearm term names the small cap-like container for an explosive charge, then the charge-bearing component itself.
More examples
- The museum displays a tin of old firing caps.
- The toy pistol uses a roll of paper caps.
- A sharp crack follows the hammer's impact on the cap.
Forms
cap · caps