hairpin

noun

Etymology: From hair + pin, 1788 (as hair pin). Adjective sense 1906 in hairpin turn etc.

1. A pin or fastener for the hair.
2. A kind of ribozyme; hairpin ribozyme.
3. A very tight bend in a road; a hairpin bend.

   “The variety of angles in the course, from slow bends to hairpins, will both test your skill as a driver and allow you the opportunity to pass other carts.”

4. An elongated horizontal v-shaped sign placed underneath a staff to indicate a crescendo or decrescendo.