Mutual

Interchangeable; reciprocal; imposing like duties and obligations; affecting two or more persons in a common transaction or relation. As, mutual — accounts, assent, covenant, credits, debts, insurance, mistake, obligations, promises, qq. v. See also Compromise; Contribution; Bargain.

Mutuality

Of contract: an obligation on each party to do or permit to be done something in consideration of the act or promise of the other.* Mutuality of obligation is generally necessary to the validity of a contract; to be binding, the contract must be enforceable by either party.* See Assent; Contract.