Aleatoric means "pertaining to luck", and derives from the Latin word alea, the rolling of dice. Aleatoric, indeterminate, or chance art is that which exploits the principle of randomness.
In some legal systems, aleatory contracts are those where the effects (outcomes) for the parties to the contract are uncertain. This may apply to gambling contracts, insurance contracts and many modern forms of derivatives and options. For example, the French civil code contains a chapter on aleatory contracts, with specific provisions for gambling and life annuities.
An example of aleatory writing is the automatic writing of the French Surrealists involving dreams, et cetera. The French literary group Oulipo for example saw no merit in aleatory work and its members altogether eliminated chance and randomness from their writing, substituting potentiality as in Raymond Queneau's Cent Mille Milliards de Poèmes (Hundred Thousand Billion Poems).
Luke Rhinehart's novel The Dice Man tells the story of a psychiatrist named Luke Rhinehart who, feeling bored and unfulfilled in life, starts making decisions about what to do based on a roll of a die.
Pierre Boulez applied the term aleatoric music to his own pieces to distinguish them from the indeterminate music of John Cage, though both are often described as aleatory. While Boulez purposefully composed his pieces to allow the performer certain liberties with regard to the sequencing and repetition of parts, Cage often composed through the application of chance operations without allowing the performer liberties. Another prolific aleatory music composer is Karlheinz Stockhausen. Qubais Reed Ghazala, founder of the circuit-bending chance-music movement, is an important contemporary chance artist also pioneering aleatoric work in visual mediums (original techniques in suminagashi, dye migration, aperture shift photography).
In film-making, there are several avant-garde examples; Fred Camper's SN (1984; first screening 2002) uses coin-flipping to determine which three of 18 possible reels to screen and what order they should go in (4896 permutations). Barry Salt, now better known as a film scholar, is known to have made a film, Permutations, six reels long which takes the word aleatory quite literally by including a customized die for the projectionist to roll to determine the reel order (720 permutations).