term:

Jus Gentium

jus gentium n

[Latin, literally, law of nations]
: a body of law recognized by nations that is binding and governs their relations with each other
: international law called also law of nations NOTE: In Roman law jus gentium referred to the rules and laws that were common to the various nations or peoples under the Roman empire and were used in cases between non-Roman citizens or between a Roman and a non-Roman citizen.

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.