We have pulled definitions from around the web and they support the definition of marriage.
This is pulled straight from a Google search for the definition of marriage. It shows that marriage is between a man and a woman.
The primary definition of marriage at Dictionary.com is between a man and a woman as well.
The definition of marriage at Merriam Webster is being united to a person of the opposite sex as husband or wife in a consensual and contractual relationship.
Oxford, keepers of the English Language, defines marriage as a formal union between an man and a woman typically recognized by law.