buckboard(n = noun.artifact) - an open horse-drawn carriage with four wheels; has a seat attached to a flexible board between the two axles;
is a kind of carriage, equipage, rig
A four-wheeled vehicle, having a long elastic board or frame resting on the bolsters or axletrees, and a seat or seats placed transversely upon it; -- called also
buckboard, n. US a horse-drawn vehicle with the body formed by a plank fixed to the axles.
Etymology:
BUCK(5) + BOARD