headrail

noun3

1. •
   The supporting rail of a blind (such as a Venetian blind) that encloses its mechanism; a headbox.
2. •
   A railing, on a sailing ship, behind the figurehead.
3. •
   [in the plural] (slang, no longer used) A person's tooth.

   • Initially, our man was the favourite, the boat's crew cheering him on as usual: 'Now my boy! Knock out his head rails' . . . — 2011