a social/cultural institution in which a union between people is recognised by society and the law. The definitions of marriage vary from culture to culture and have changed throughout time.
In the West, this has typically been a union between two people under the authority of the state representing God, that legally and morally allows for sexual intercourse and family raising (and thus, any sexual activity or children produced outside of marriage as being lesser or even illegal).
The definition of marriage has changed in the West; firstly, it is no longer a requirement for the marriage to be religious in nature or recognised and allowed by any religious institution: these are known as civil marriages. The age of consent for marriage has also changed, as have the legal rights and responsibilities within them: a pertinent example being that a wife is no longer considered a husband’s property through marriage, and no longer does the husband automatically hold all of his wife’s assets.
A cultural variant in marriage also occurs in monogamous and polygamous marriage; many countries in the world allow for (predominantly men) to be married to more than one person; whereas in most countries in the West, this is considered bigamy and is illegal.