\EY-lee-uh-tawr-ee, -tohr-ee, AL-ee-\
1. of or pertaining to accidental causes; of luck or chance; unpredictable: an aleatory element.
2. Law. depending on a contingent event: an aleatory contract.
3. Music. employing the element of chance in the choice of tones, rests, durations, rhythms, dynamics, etc.
…it was not a matter of reduction at all, but—perversely—of expansion, the aleatory flutter of uncontrolled, metastatic growth… — David Foster Wallace, Infinite Jest, 1996
[Man] is supposed to love happiness; it is my contention that he rather loves excitement. Danger, enterprise, hope, the novel, the aleatory, are dearer to man than regular meals. — Robert Louis Stevenson, The Day After To-morrow, 1866
Hailing from the Latin word meaning “the dice” or “chance” alea, aleatory first surfaced in English in the late seventeenth century.