If you’re at the piano and play three or more notes at the same time, you’re playing a chord. Chords, which you can play with one or both hands, have but one simple goal in life: to provide harmony.

You hear chords all the time in the sounds of a barbershop quartet, a church choir, and a sidewalk accordion player (monkey with tip jar is optional). Even the sound of a car horn is a chord, albeit a headache-inducing one.

Chords begin very simply. Like melodies, chords are based on scales. To make a chord, you select any note and put other scale notes on top of it. Most chords begin as triads — three notes added together. A triad consists of a root note and two other notes: a third interval and a fifth interval:

This C chord is a simple triad.
This C chord is a simple triad.

In a C chord, which is a typical triad, C is the root note, E is a third interval from C, and G is a fifth interval from C.

You can build new chords by altering this C triad in any of the following ways:

  • Raising or lowering notes of the triad by a half-step or whole-step

  • Adding notes to the triad

  • Both raising or lowering notes and adding notes