The modern English word "marriage" derives from Middle English mariage, which first appears in 1250–1300 C.E. This in turn is derived from Old French marier (to marry) and ultimately Latin marītāre (to marry) and marītus (of marriage).
Anthropologists have proposed several competing definitions of marriage so as to encompass the wide variety of marital practices observed across cultures. In his book The History of Human Marriage (1921), Edvard Westermarck defined marriage as "a more or less durable connection between male and female lasting beyond the mere act of propagation till after the birth of the offspring." In The Future of Marriage in Western Civilization (1936), he rejected his earlier definition, instead provisionally defining marriage as "a relation of one or more men to one or more women that is recognised by custom or law".
The anthropological handbook Notes and Queries (1951) defined marriage as "a union between a man and a woman such that children born to the woman are the recognized legitimate offspring of both partners." In recognition of a practice by the Nuer of Sudan allowing women to act as a husband in certain circumstances, Kathleen Gough suggested modifying this to "a woman and one or more other persons."
Edmund Leach criticized Gough's definition for being too restrictive in terms of recognized legitimate offspring and suggested that marriage be viewed in terms of the different types of rights it serves to establish. Leach expanded the definition and proposed that "Marriage is a relationship established between a woman and one or more other persons, which provides that a child born to the woman under circumstances not prohibited by the rules of the relationship, is accorded full birth-status rights common to normal members of his society or social stratum" Leach argued that no one definition of marriage applied to all cultures. He offered a list of ten rights associated with marriage, including sexual monopoly and rights with respect to children, with specific rights differing across cultures.
Duran Bell also criticized the legitimacy-based definition on the basis that some societies do not require marriage for legitimacy, arguing that in societies where illegitimacy means only that the mother is unmarried and has no other legal implications, a legitimacy-based definition of marriage is circular. He proposed defining marriage in terms of sexual access rights.
Marriage is a social union or legal contract between people that creates kinship. It is an institution in which interpersonal relationships, usually intimate and sexual, are acknowledged in a variety of ways, depending on the culture or subculture in which it is found. Such a union, often formalized via a wedding ceremony, may also be called matrimony.
People marry for many reasons, including one or more of the following: legal, social, emotional, economical, spiritual, and religious. These might include arranged marriages, family obligations, the legal establishment of a nuclear family unit, the legal protection of children and public declaration of commitment.
Marriage practices are very diverse across cultures, yet almost every known society has had some form of marriage between a man and a woman. In some societies an individual is limited to being in one such couple at a time (monogamy), while other cultures allow a male to have more than one wife (polygyny) or, less commonly, a female to have more than one husband (polyandry). Some societies also allow marriage between two males or two females. Societies frequently have other restrictions on marriage based on the ages of the participants, pre-existing kinship, and membership in religious or other social groups.
The act of marriage usually creates normative or legal obligations between the individuals involved. In some societies these obligations also extend to certain family members of the married persons. Almost all cultures that recognize marriage also recognize adultery as a violation of the terms of marriage, and forbid incestuous marriages. In cultures that allow the dissolution of a marriage this is known as divorce.
Marriage is usually recognized by the state, a religious authority, or both. It is often viewed as a contract. Civil marriage is the legal concept of marriage as a governmental institution irrespective of religious affiliation, in accordance with marriage laws of the jurisdiction. If recognized by the state, by the religion(s) to which the parties belong or by society in general, the act of marriage changes the personal and social status of the individuals who enter into it.