The Collaborative International Dictionary of English v.0.48:
Aleatory \A"le*a*to*ry\, a. [L. aleatorius, fr. alea chance, die.] (Law) Depending on some uncertain contingency; as, an aleatory contract. --Bouvier. [1913 Webster]WordNet (r) 3.0 (2006):
aleatory adj 1: dependent on chance; "the aleatory element in life"