tetrads
Tetrad Chords / Seventh Chords - Music Theory with Guitar Shapes
What's a Tetrad ?
A basic chord is built with three notes this is what we call "triad chords" or "triads". Tetrad chords aka "four note-chords" or "seventh chords" are simply chords containing four notes, “tetra“ is a Greek root meaning four. Tetrads can be seen as triads with an additional note which can be a major seventh (7) or a minor seventh (b7).
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