A doghouse, known in British English as a kennel, is a small shed commonly built in the shape of a little house intended for a dog. It is a structure in which a dog is kept or can run into for shelter from the elements.
It should not be too big or too small for the intended dog because of the potential for excessive heat loss or excessive constriction.

Other terminology

Architecture

In architecture, "doghouse" is commonly a builder/contractor term for a dormer. The name is derived from the appearance of improperly proportioned dormers, which do resemble dog houses. A properly proportioned dormer should neatly fit over the window it is meant to frame. A common mistake is to undersize the windows or oversize the dormer, which necessitates the use of siding or other infill material with the structure treated as a gable end. Some architects use the word "doghouse" in a derogatory manner to indicate an ignorance of "honest" building practices often found in low-cost residential and light commercial, developer-built structures. See also pork chop eave.

Double bass

The double bass is also sometimes jokingly referred to as a doghouse due to its largeness of sound, especially by jazz or bluegrass musicians.

In the doghouse

The idiom 'In the doghouse/Land yourself in the doghouse' means out of favour and in trouble with a person/people because of an offence/caused upset, for example for a husband who is figuratively sent to the doghouse in the same way that a dog is removed from the human habitation. This is the principal usage of the expression dog house in British English.