Use of two keys at once. Typically a bitonal passage will have two voices or groups of voices each playing in its own key. Stravinsky, in the Diaghilev ballets, relies frequently on bitonality. See also polytonality .

the use of two tonalities (or keys) at the same time. This does not imply, for instance, sudden or rapid modulation from one key to another but rather a passage or work in which two distinct keys are used simultaneously.

The simultaneous juxtaposition of two keys (e.g., C Major and F minor). Some 20th century composers who utilized bitonality as a common device were Charles Ives and Darius Milhaud.