In civil law systems, a synallagmatic contract is a

contract A contract is an agreement that specifies certain legally enforceable rights and obligations pertaining to two or more parties. A contract typically involves consent to transfer of goods, services, money, or promise to transfer any of thos ...

in which each party to the contract is bound to provide something to the other party. Its name is derived from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

συνάλλαγμα (''synallagma''), meaning mutual agreement. Examples of synallagmatic contracts include contracts of sale, of service, or of hiring. In

common law Common law (also known as judicial precedent, judge-made law, or case law) is the body of law primarily developed through judicial decisions rather than statutes. Although common law may incorporate certain statutes, it is largely based on prece ...

jurisdictions, it is roughly the equivalent of a

bilateral contract A contract is an agreement that specifies certain legally enforceable rights and obligations pertaining to two or more parties. A contract typically involves consent to transfer of goods, services, money, or promise to transfer any of those at ...

and may be contrasted with a

gift A gift or present is an item given to someone (who is not already the owner) without the expectation of payment or anything in return. Although gift-giving might involve an expectation of reciprocity, a gift is intended to be free. In many cou ...

(as such a relationship is not one of contract) or a

unilateral contract A contract is an agreement that specifies certain legally enforceable rights and obligations pertaining to two or more Party (law), parties. A contract typically involves consent to transfer of goods, Service (economics), services, money, or pr ...

in which only one party makes an enforceable promise. In his comments on the case of Hong Kong Fir Shipping Co Ltd. v Kawasaki Kisen Kaisha Ltd. (1957),

Lord Diplock William John Kenneth Diplock, Baron Diplock, (8 December 1907 – 14 October 1985) was a British barrister and judge who served as a lord of appeal in ordinary between 1968 and until his death in 1985. Appointed to the English High Court in ...

said: :"Every synallagmatic contract contains in it the seeds of the problem - in what event will a party be relieved of his undertaking to do that which he has agreed to do but has not yet done?" England and Wales Court of Appeal (Civil Division) Decision: Hong Kong Fir Shipping Co Ltd. v Kawasaki Kisen Kaisha Ltd.
accessed 3 May 2016

References

Civil law (legal system) Contract law {{Law-term-stub