hairpin

noun4

1. •
   A pin or fastener for the hair.
2. •
   [before a noun] 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. — 2009
3. •
   An elongated horizontal v-shaped sign placed underneath a staff to indicate a crescendo or decrescendo.
4. •
   A kind of ribozyme; hairpin ribozyme.