Synallagmatic contract

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In civil law systems, a synallagmatic contract is a contract in which each party to the contract is bound to provide something to the other party.{{Cite book|url = http://www.oxfordreference.com/view/10.1093/acref/9780199664924.001.0001/acref-9780199664924-e-378#|title = Bilateral Contract|last = Law|first = Jonathan|date = 2015|website = Oxford Dictionary of Law|publisher = Oxford Reference| isbn=978-0-19-966492-4 |access-date = March 27, 2016}} Its name is derived from the Ancient Greek συνάλλαγμα (synallagma), meaning mutual agreement.{{Cite web|url = http://referenceworks.brillonline.com/entries/brill-s-new-pauly/synallagma-e1127030|title = Synallagma|last =|first =|date =October 2006|website = Brill's New Pauly|publisher = BrillOnline Reference Works|access-date = March 27, 2016}} Examples of synallagmatic contracts include contracts of sale, of service, or of hiring.

In common law jurisdictions, it is roughly the equivalent of a bilateral contract and may be contrasted with a gift (as such a relationship is not one of contract) or a unilateral contract 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 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?" [https://www.bailii.org/ew/cases/EWCA/Civ/1961/7.html England and Wales Court of Appeal (Civil Division) Decision: Hong Kong Fir Shipping Co Ltd. v Kawasaki Kisen Kaisha Ltd.], accessed 3 May 2016