high seat

noun4

1. •
   A seat that it situated above others, as on a raised platform, to be used by dignitaries, royalty, etc.
2. •
   A highchair.
3. •
   A raised hide from which game is shot at.
4. •
   An external seat on or near the roof of a carriage or coach.

   • [T]he young man helped the young lady, half-swooning, inside, and Egbert, Murial Jane and Silvander Dan climbed on to the boot which was a handsome high-seat at the back. — 1936