Aleatoricism is the incorporation of chance into the process of creation, especially the creation of art or media. The word derives from the Latin word alea, the rolling of dice. It should not be confused with either improvisation or indeterminacy.
Improvisation is the process of devising a solution to a requirement by making-do, despite absence of resources that might be expected to produce a solution. In a technical context, this can mean adapting a device for some use other than that which it was designed for, or building a device from unusual components in an ad-hoc fashion. Improvisation in the context of performing arts is spontaneous performance without specific preparation.
The classic definition of indeterminacy derives from John Cage, according to which indeterminacy “refers to the ability of a piece to be performed in substantially different ways” (Pritchett 1993, 108). Bryan Simms thus conflates indeterminacy with what Cage called chance composition when he claims that “Any part of a musical work is indeterminate if it is chosen by chance, or if its performance is not precisely specified. The former case is called ‘indeterminacy of composition’; the latter is called “indeterminacy of performance” (Simms 1986, 357).