A roommate is a person with whom one shares a living facility such as a room or dormitory except when being family or romantically involved. Similar terms include dorm-mate, suite-mate, housemate, or flatmate ("flat": the usual term in British English for an apartment). Flatmate is the term most commonly used in New Zealand, when referring to the rental of an unshared room within any type of dwelling. Another similar term is sharemate (shared living spaces are often called sharehouses in Australia and other Commonwealth countries). A sharehome is a model of household in which a group of usually unrelated people reside together, including lease-by-room arrangements. The term generally applies to people living together in rental properties rather than in properties in which any resident is an owner occupier. In the United Kingdom, the term "roommate" means a person sharing the same bedroom; in the United States and Canada, "roommate" and "housemate" are used interchangeably regardless of whether a bedroom is shared, although at US universities having a roommate commonly implies sharing a bedroom. This article uses the term "roommate" in the US sense of a person one shares a residence with who is not a relative or significant other. The informal term for roommate is roomie, which is commonly used by university students and members of the younger generation.
The most common reason for sharing housing is to reduce the cost of housing. In many rental markets, the monthly rent for a two- or three-bedroom apartment is proportionately less per bedroom than the rent for a one-bedroom apartment (in other words, a three-bedroom flat costs more than a one-bedroom, but not three times as much). By pooling their monthly housing money, a group of people can achieve a lower housing expense at the cost of less privacy. Other motivations are to gain better amenities than those available in single-person housing, to share the work of maintaining a household, and to have the companionship of other people.
