In general, an augmented chord is any chord which contains an augmentedinterval. An augmented sixth chord, for instance, has an augmented sixth between the highest and lowest notes. More specifically, the augmented chord is the three-note chord consisting of a major third and augmented fifth above the root — if the root is C, the augmented chord consists of the notes C, E and G♯. It can also be thought of as two major thirds stacked on top of one another, and thus resembles a major chord with a raised fifth. This particular chord is also known as the augmented triad. In twelve tone equal tempered tuning, an augmented chord has 4 semitones between the third and fifth, 4 between the root and third, and 8 between the root and fifth. It is represented by the integer notation 0,4,8. The augmented chord is considered dissonant, or unstable, and lacks tonal center or drive. It symmetrically divides the octave and is ambiguous as to root because an augmented chord built from any note of an augmented chord produces that same chord. So, for example, a C augmented chord consists of the notes C, E and G♯, but since any note can be the root, a C augmented chord is also an E augmented chord and a G♯ augmented chord. This makes accompaniment for rhythm instruments easier, as there are many shapes for the same augmented chord.
