Final answer:
Marriage is the legally recognized relationship between two individuals who live together and share a domestic lifestyle. It is a social contract based on a sexual relationship and implies permanence. Marriage may vary in different cultures and can involve legal, religious, and other variations.
Step-by-step explanation:
A legally or policy defined relationship between two individuals who live together and share a domestic lifestyle is called marriage. Marriage is a legally recognized social contract between two people, traditionally based on a sexual relationship and implying a permanence of the union. It can vary across cultures and may involve variations such as a legal union, involvement of more than two people, or whether it is religious or civil.