Dsus4 is an abbreviated way of saying D suspended 4th. The 4th in this case is G, the 4th of the D major scale. The G replaces the 3rd (F#), meaning sus chords are neither major nor minor; it’s ...

They are so commonplace that we take the theory behind them for granted. Here are five 7th chords, the theory underpinning them, and some ideas for modifying them ...