from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
RECIPROCAL CONTRACT, civil law. One in which the parties enter into mutual
engagements.
2. They are divided into perfect and imperfect. When they are perfectly
reciprocal, the obligation of each of the parties is equally a principal
part of the contract, such as sale, partnership, &c. Contracts imperfectly
reciprocal are those in which the obligation of one of the parties only is a
principal obligation of the contract; as, mandate, deposit, loan for use,
and the like. In all reciprocal contracts the consent of the parties must be
expressed. Poth. Obl. n. 9; Civil Code of Louis. art. 1758, 1759.