![tappet tappet](https://www.tekportal.net/wp-content/uploads/2018/11/tappet.jpg)
noun Machinery.
- a sliding rod, intermittently struck by a cam, for moving another part, as a valve.
noun
- a mechanical part that reciprocates to receive or transmit intermittent motion, esp the part of an internal-combustion engine that transmits motion from the camshaft to the push rods or valves