tailboard(n = noun.artifact) tailgate - a gate at the rear of a vehicle; can be lowered for loading;
is a kind of gate
is a part of beach waggon, beach wagon, estate car, station waggon, station wagon, waggon, wagon, motortruck, truck
The board at the rear end of a cart or wagon, which can be removed or let down, for convenience in loading or unloading. [1913 Webster]
tailboard, n. a hinged or removable flap at the rear of a lorry etc.