term:

Synallagmatic

synallagmatic adj

[Greek synallagmatikos of a contract, from synallagmat- synallagama contract, covenant, from synallassein to enter into a contract, from syn- together with, at the same time as + allassein to change, exchange, barter, from allos other]
in the civil law of Louisiana
: bilateral

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