How do I call the back of a pick up?

I heard it's called the بستر یا the box? I dunno o3o

Here in Aus, what آپ call pick up trucks we call "utes", the back of which are called "the tray". Though in normal car it would just be a "boot".

Tempted to start a فورم called "I say tomato, آپ say..." and have people put their own regional words یا pronunciations, then have others تبصرہ and put their own equivalent. Could be interesting... یا maybe I'm just a linguistics nerd xD

The deck. I think our main NZ brand is Tuff Deck.