catflap.org Online Dictionary Query

  synallagmatic contract /sˌɪnɐlɐɡmˈatɪk kˈɒntɹakt/
  gegenseitiger Vertrag, synallagmatischer Vertrag
     Synonym: reciprocal 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
  

  SYNALLAGMATIC CONTRACT, civil law. A synallagmatic or bilateral contract is 
  one by which each of the contracting parties binds himself to the other; 
  such are the contracts of sale, hiring, &c. Poth. Ob. n. 9. Vide Contract.