term:

Aleatory

aleatory adj

[Latin aleatorius of a gambler, from aleator gambler, dice player, from alea, a dice game]
: depending on an uncertain event or contingency as to both profit and loss [the nature of a lawyer's contingency fee arrangement]

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