(Latin: con, together; trahere, to draw)
An agreement by which two or more persons mutually bind themselves to give, do, or abstain from something.
It requires mutual consent clearly manifested by the parties on both sides, so that there may be no substantial mistake or fraud or misrepresentation on either side; the consent must be deliberate and free, and the subject matter must be definite and certain, possible and honest.
Marriage is a form of contract which Christ raised to the dignity of a Sacrament.
New Catholic Dictionary