The definition of marriage changes by generation and by culture

The definition of marriage changes by generation and by culture. Today, the term
marriage does not necessarily mean only one man and one woman. Some might define
marriage as inclusive of same-sex couples, and still others might define marriage as
allowing for polygamist relationships. How do you define marriage? Your audience is an
English teacher. (Tip: Just because you are providing your definition of marriage does
not mean you use first person. This essay requires the third person point of view.)