In reading about a flintlock rifle, I encountered the word "frizzen". I think it is the steel plate
from which the flint struck the spark to ignite the powder in the pan. I have not yet been
able find its etymology.

Flint Lock

The original flint locks were marked either:
"HARPERS/FERRY/(date)" or "SPRING/FIELD/(date)".
The lock was produced to accept a standard 1" flint.
The hammer, top jaw, and screw were made of steel, as was the frizzen.
The pan was of brass.
All internal parts - the mainspring, sear, sear spring, frizzen spring,
and tumbler, as well as the corresponding screws, were produced of
steel and in many respects resembled the French Charleville which,
after successfull use in the Revolution, became a model for future US. muskets.
The lockplate was unremarkable, measuring 6 5/8 inches long.

PS: I haven't been able to find "frizzen" in any dictionary, let alone find etymology. But look
at this, from Illinois Deer Hunting Regulations:
"Definition of an unloaded muzzleloading firearm: removal of percussion cap; or removal of prime
powder from frizzen pan with frizzen open and hammer all the way down; or removal of prime
powder from flash-pan and wheel unwound; or removal of prime powder with match not lit.