A doghouse, also known as a kennel in British English, 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.
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.
The idiom ‘(land oneself) in the doghouse’ means (become) out of favour and in trouble with a person/people because of an offence/caused upset, for example of 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 doghouse in British English.