catflap.org Online Dictionary Query

  reciprocal contract /ɹɪsˈɪpɹəkəl kˈɒntɹakt/
  gegenseitiger Vertrag, synallagmatischer Vertrag
     Synonym: synallagmatic contract
  
   see: contract, contracts, basic contract, base contract, underlying contract, subsequent contract, model contract, fictitious contract, feigned contract, sham contract, express contract, unilateral contract, executed contract, fictitious contract, informal contract, formal contract, deed, simple contract, verbal contract, implied contract, executory contract, contract expires, be contracted, unsigned
  

  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.