¹ a; the social institution under which a man and woman establish their decision to live as husband and wife by legal commitments, religious ceremonies, etc.
b; a similar institution involving partners of the same gender: gay marriage.
² the state, condition, or relationship of being married; wedlock: a happy marriage.
³ the legal or religious ceremony that formalizes the decision of two people to live as a married couple, including the accompanying social festivities: to officiate at a marriage.
⁴ a relationship in which two people have pledged themselves to each other in the manner of a husband and wife, without legal sanction: trial marriage.