Find the odd number / letters / word from the given alternative:

Den
Roof
Burrow
Nest

The odd word in the given list is “roof”. The other words, “den”, “burrow”, and “nest”, are all places where animals live. A roof is a structure that covers a building or other structure to protect it from the weather. It is not a place where animals live.

A den is a natural or artificial shelter used by animals, typically a wild animal. It can be a hole in the ground, a cave, or a hollow tree.

A burrow is a hole or tunnel dug in the ground by an animal for shelter. It can be used by a variety of animals, including rabbits, moles, and snakes.

A nest is a structure built by a bird or other animal for laying eggs and raising young. It can be made of a variety of materials, including twigs, leaves, and grass.