Augmented chords
An augmented triad stacks two major thirds: root, major third, augmented fifth (Caug: C–E–G♯). It splits the octave into three equal parts, so like the diminished seventh it is symmetric — C aug, E aug and G♯ aug contain the same notes.
That raised fifth gives the chord a dreamlike, unresolved shimmer — think of the intro to "Oh! Darling" or the end of a silent-movie chase. The augmented dominant (C7♯5) sharpens a V7's pull even further, and maj7♯5 is a modern jazz color over major harmony.
Augmented chords usually appear in passing: raise the fifth of a static major chord one semitone and keep going (C → Caug → C6) and you get the classic "line cliché" heard in countless ballads. Try it under a melody note that stays put.
