Tritone The interval to the augmented fourth (thus, literally, three full tones), such as C to F#, often used to denote malevolence, temptation, or any similar expression of evil.
A tritone can travel in either direction. An interval from C to the F# above it and one from C to the F# below it would both be tritones.
Because of its harsh and unexpected dissonance, the tritone was known in medieval times as diabolus in musica, or "the devil in music," and was forbidden to be played in the music of the church of Rome.
Though hardly the work of the devil, the tritone appears in the score of West Side Story in many roles, thanks to the apparently limitless expertise of its composer: the restless anticipating "Something’s Coming," the brassy opening of The Dance at the Gym, the richly romantic "Maria," and the jumpy "Cool," to name but a few.
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