A tailboard is the flat board at the back of a truck or a cart that can be let down or taken off, so that things can be loaded on and off. When it is up, it holds the load in; when it is down, it makes a low shelf you can slide boxes across, or sit on while you eat your lunch. The thing itself is completely ordinary; the word is the part worth watching. Tailboard is the older, more British word. In American English almost everyone says tailgate instead, and tailgate has been spreading into British use too, so tailboard now sounds a little old-fashioned, or like the word a farmer or an older builder would use. You will still meet it in books and in the speech of older speakers. There is one more reason to keep the two words apart. Tailgate has grown extra lives that tailboard does not have: it is also a verb meaning to drive too close behind another car, and in America a tailgate party is eating and drinking in a car park before a game. Tailboard means only the board. Say it TAIL-bord, with the stress on the first part.

（貨車、推車的）後車板、尾板