A bunk bed is a type of bed in which one bed is stacked on top of another. To get to the second bunk a ladder is used, though taller children often find other faster, more creative methods of climbing into them.They are typically used as furnishings in children's rooms, or university residence hall bedrooms allowing two people to sleep in the same room while maximizing available floor space. They normally are supported by four poles at each corner of the bed.