Legal Definition of a Domestic Partner
Jurisdictions that recognise domestic partnerships under the law, treat the relationship similar to a marriage in that the couple can benefit from each other's medical benefits or pension plans. Cohabiters can be of the same sex, which is the basis some states use to recognise same-sex unions.
A domestic partnership is a personal relationship between two individuals living together and sharing a common domestic life together, but not joined by marriage, civil union or any other type of legal partnership. A domestic partnership can consist of two people who are not of the opposite sex.
In some jurisdictions, a domestic partnership is treated the same as a marriage, such that a cohabiter can benefit from health insurance through his cohabiter's employer. Cohabiters can enter into a domestic partnership agreement similar to a prenuptial agreement to contractually agree to matters of finance, property or shared responsibilities.
A domestic partnership is also referred to as companion, spousal equivalent or "POSSLQ" (person of the opposite sex sharing living quarters). The U.S. Census Bureau uses the term "POSSLQ" in capturing data.