Augmented third

In classical music from Western culture, an augmented third () is an interval produced by widening a major third by a chromatic semitone^[1][3]. For instance, the interval from C to E is a major third, four semitones wide, and both the intervals from C♭ to E, and from C to E♯ are augmented thirds, spanning five semitones. Being augmented, it is considered a dissonant interval^[4].

Its inversion is the diminished sixth, and its enharmonic equivalent is the perfect fourth.

Sources

1. ^ ^{a b} Benward & Saker (2003). Music: In Theory and Practice, Vol. I, p.54. ISBN 978-0-07-294262-0.
2. ^ Haluska, Jan (2003). The Mathematical Theory of Tone Systems, p.xxvi. ISBN 0824747143. Classic augmented third.
3. ^ Hoffmann, F.A. (1881). Music: Its Theory & Practice, p.89-90. Thurgate & Sons. Digitized Aug 16, 2007. Archaically: superfluous third.
4. ^ Benward & Saker (2003), p.92.