An augmented chord is a triad that consists of three notes: the root, the major third, and the augmented fifth. It is different from a major chord in that it has an augmented fifth.
The formula 1-3-#5 represents the intervallic structure of an augmented chord:
For example, in a C augmented chord:
The combination of these three notes (C, E, G#) creates the sound of a C augmented chord.
Augmented chords have a unique and somewhat dissonant quality due to the augmented 5th interval. They are often used for creating tension or leading to a resolution in music. Augmented chords are less common than major and minor chords but add color to compositions.
On a piano or keyboard, augmented chords are typically played by pressing the root note, the major third, and the augmented fifth.
In guitar playing, augmented chords are formed by pressing down specific combinations of strings and frets, following chord diagrams or finger positions.