buck ‧ board /ˈbʌkbɔːd $ -bɔːrd/ BrE AmE noun [countable]
[ Date: 1600-1700 ; Origin: buck 'main structure of a carriage or cart' (17-19 centuries) (perhaps from bouk 'body, belly' (11-19 centuries) , from Old English buc ; ⇨ ↑ bucket ) + board ]
a light vehicle with four wheels that is pulled by a horse, and was used in the US in the 19th century