sprocket

noun

Etymology: Unknown. First attested in the 16th century. Perhaps related to Italian rocchetto (“spool”), spoletta (“spool”), sprone (“spur”), or English spoke, spike, spur.

1. A toothed wheel that enmeshes with a chain or other perforated band.
2. The tooth of such a wheel.
3. A flared extension at the base of a sloped roof.
4. A placeholder name for an unnamed, unspecified, or hypothetical manufactured good or product.

   “Suppose we have a widget factory that produces 100 widgets per year, and a sprocket factory that produces 200 sprockets per year.”