Etymology

Noun

1. A tool with a heavy head and a handle used for pounding.
2. A moving part of a firearm that strikes the firing pin to discharge a gun.
3. The malleus.
4. In a piano or dulcimer, a piece of wood covered in felt that strikes the string.
5. A device made of a heavy steel ball attached to a length of wire, and used for throwing.
6. The last rock in an end.
7. A frisbee throwing style in which the disc is held upside-down with a forehand grip and thrown above the head.

Verb

1. To strike repeatedly with a hammer, some other implement, the fist, etc.
2. To emphasize a point repeatedly.
3. To hit particularly hard.
4. To strike internally, as if hit by a hammer.

   I could hear the engine’s valves hammering once the timing rod was thrown.