A household consists of two or more persons who live in the same dwelling. It may be of a single family or another type of person group. The household is the basic unit of analysis in many social, microeconomic and government models, and is important to economics and inheritance. Household models include families, blended families, shared housing, group homes, boarding houses, houses of multiple occupancy (UK), and single room occupancy (US). In feudal societies, the royal household and medieval households of the wealthy included servants and other retainers. Government definitions For statistical purposes in the United Kingdom, a household is defined as "one person or a group of people who have the accommodation as their only or main residence and for a group, either share at least one meal a day or share the living accommodation, that is, a living room or sitting room". The introduction of legislation to control houses of multiple occupations in the UK Housing Act (2004) required a tighter definition of a single household. People can be considered a household if they are related: full- or half-blood, foster, step-parent/child, in-laws (and equivalent for unmarried couples), a married couple or unmarried but "living as ..." (same- or different-sex couples). The United States Census definition also hinges on "separate living quarters": "those in which the occupants live and eat separately from any other persons in the building." According to the U.S. census, a householder is the "person (or one of the people) in whose name the housing unit is owned or rented (maintained)"; if no person qualifies, any adult resident of a housing unit is considered a householder. The U.S. government formerly used "head of the household" and "head of the family", but those terms were replaced with "householder" in 1980. In the census definition of a household, it On July 15, 1998, Statistics Canada said: "A household is generally defined as being composed of a person or group of persons who co-reside in, or occupy, a dwelling." Economic definition Although a one-income-stream economic theory simplifies modeling, it does not necessarily reflect reality. Many, if not most, households have several income-earning members. Most economic models do not equate households and traditional families, and there is not always a one-to-one relationship between households and families. Social definitions In social work, a household is defined similarly: a residential group in which housework is divided and performed by householders. Care may