Experimental music is a term introduced by composer John Cage in 1955. According to Cage's definition, "an experimental action is one the outcome of which is not foreseen" (Cage 1961), and he was specifically interested in completed works that performed an unpredictable action.

In a broader sense, it is also used to mean any music that challenges the commonly accepted notions of what music is. David Cope describes experimental music as that, "which represents a refusal to accept the status quo"