Marriage is a social union or legal contract between individuals that creates Kinship. It is an institution in which interpersonal relationships are acknowledged by a variety of ways, depending on the culture or demographic. Such a union may also be called matrimony while the ceremony that marks its beginning is usually called a wedding and the marital structure created is known as wedlock.

People marry for many reasons, most often including one or more of the following: legal, social, emotional, economical, spiritual, and religious. These might include arranged marriages, family obligations, and the legal establishment of a nuclear family unit, the legal protection of children and public declaration of love.

According to Confucius, "Marriage is the union (of the representatives) of two different surnames, in friendship and in love, in order to continue the posterity of the former sages, and to furnish those who shall preside at the sacrifices to heaven and earth, at those in the ancestral temple, and at those at the altars to the spirits of the land and grain."

Marriage practices are very diverse across cultures, may take many forms, and are often formalized by a ceremony called a wedding. 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.

External recognition can manifest in a variety of ways. Some examples include 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