1) BBC Radio 4 programme 2) Camp sight 3) Double-decker furniture 4) Either of these two beds 5) One of two sleepers, usually 6) Sack in a stack 
A bunk bed is a type of bed in which one bed frame is stacked on top of another. The nature of bunk beds allows two or more people to sleep in the same room while maximizing available floor space for activities. This leads to them being used in places with limited floor space, such as on ships and in army garrisons or in places where bedspace need...
[n] - beds built one above the other
noun beds built one above the other
a piece of furniture consisting of two single platformlike beds connected one above the other. · either of these two beds.