doghouse n.

"quadruped of the genus Canis," Old English docga, a late, rare word, used in at least one Middle English source in reference specifically to a powerful breed of canine; other early Middle English uses tend to be depreciatory or abusive. Its origin remains one of the great mysteries of English etymology.

The word forced out Old English hund (the general Germanic and Indo-European word, from root from PIE root *kwon-) by 16c. and subsequently was picked up in many continental languages (French dogue (16c.), Danish dogge, German Dogge (16c.). The common Spanish word for "dog," perro, also is a mystery word of unknown origin, perhaps from Iberian. A group of Slavic "dog" words (Old Church Slavonic pisu, Polish pies, Serbo-Croatian pas) likewise is of unknown origin. 

In reference to persons, by c. 1200 in abuse or contempt as "a mean, worthless fellow, currish, sneaking scoundrel." Playfully abusive sense of "rakish man," especially if young, "a sport, a gallant" is from 1610s. Slang meaning "ugly woman" is from 1930s; that of "sexually aggressive man" is from 1950s.  

Many expressions — a dog's life (c. 1600), go to the dogs (1610s), dog-cheap (1520s), etc. — reflect the earlier hard use of the animals as hunting accessories, not pets. In ancient times, "the dog" was the worst throw in dice (attested in Greek, Latin, and Sanskrit, where the word for "the lucky player" was literally "the dog-killer"), which plausibly explains the Greek word for "danger," kindynos, which appears to be "play the dog" (but Beekes is against this).

Notwithstanding, as a dog hath a day, so may I perchance have time to declare it in deeds. [Princess Elizabeth, 1550]

Meaning "something poor or mediocre, a failure" is by 1936 in U.S. slang. From late 14c. as the name for a heavy metal clamp of some kind. Dog's age "a long time" is by 1836. Adjectival phrase dog-eat-dog "ruthlessly competitive" is by 1850s. Phrase put on the dog "get dressed up" (1934) may be from comparison of dog collars to the stiff stand-up shirt collars that in the 1890s were the height of male fashion (and were known as dog-collars from at least 1883).

And Caesar's spirit, ranging for revenge,

With Ate by his side come hot from Hell,

Shall in these confines with a monarch's voice

Cry Havoc! and let slip the dogs of war;

[Shakespeare, "Julius Caesar"]

Old English hus "dwelling, shelter, building designed to be used as a residence," from Proto-Germanic *hūsan (source also of Old Norse, Old Frisian hus, Dutch huis, German Haus), of unknown origin, perhaps connected to the root of hide (v.) [OED]. In Gothic only in gudhus "temple," literally "god-house;" the usual word for "house" in Gothic being according to OED razn.

Meaning "family, including ancestors and descendants, especially if noble" is from c. 1000. Zodiac sense is first attested late 14c. The legislative sense (1540s) is transferred from the building in which the body meets. Meaning "audience in a theater" is from 1660s (transferred from the theater itself, playhouse). Meaning "place of business" is 1580s. The specialized college and university sense (1530s) also applies to both buildings and students collectively, a double sense found earlier in reference to religious orders (late 14c.). As a dance club DJ music style, probably from the Warehouse, a Chicago nightclub where the style is said to have originated.

To play house is from 1871; as suggestive of "have sex, shack up," 1968. House arrest first attested 1936. House-painter is from 1680s. House-raising (n.) is from 1704. On the house "free" is from 1889. House and home have been alliteratively paired since c. 1200.

And the Prophet Isaiah the sonne of Amos came to him, and saide vnto him, Thus saith the Lord, Set thine house in order: for thou shalt die, and not liue. [II Kings xx.1, version of 1611]