Toe-mayto, Toe-mahto

If you were an animal owner, and you arranged something like this, with a barracade in the front, a black sheet over the top to cut out light, and gave a bowl of snacks to the animal... it might be called a cage.

Throw in books and a DVD player with children instead, and it's called a FORT.

Same thing.

Cage (pronounce: kayj)
-noun: a device created to enclose or confine, usually created to keep mice, monkeys, etc.
-verb: to confine in, or to keep enclosed, as in caging in small animals for keeping.