aleatory (adj.)

"of uncertain outcome, depending on a contingent event," literally "depending on the throw of a die," 1690s, from Latin aleatorius "pertaining to a gamester," from aleator "a dice player," from alea "a game with dice; chance, hazard, risk; a die, the dice;" perhaps literally "a joint-bone" (marked knuckle-bones used as early dice), "a pivot-bone," and related to axis. Aleatoric "incorporating chance and randomness" was used as a term in the arts from 1961.