Contract

n.
  1. (Law) The agreement of two or more persons, upon a sufficient consideration or cause, to do, or to abstain from doing, some act; an agreement in which a party undertakes to do, or not to do, a particular thing; a formal bargain; a compact; an interchange of legal rights.
  2. A formal writing which contains the agreement of parties, with the terms and conditions, and which serves as a proof of the obligation.
  3. The act of formally betrothing a man and woman.