In 1702, German composer Andreas Werckmeister cited the phrase “mi contra fa est diabolus in musica,” a Latin phrase meaning “mi against fa is the devil in music,” (“mi” and “fa” are common terms used ...

For centuries, it was called the devil's interval — or, in Latin, diabolus in musica. In music theory, it's called the "tritone" because it's made of three whole steps. "The reason it's ...