A chord is a musical term for three or more notes played at the same time, creating a richer, fuller sound than a single note alone. When a pianist presses down multiple keys together or a guitarist strums several strings at once, they're playing a chord.

Chords form the foundation of most music you hear. That opening of “Let It Be” by the Beatles? Chords. The background music in your favorite movie? Built on chords. When you sing “Happy Birthday” and someone plays piano along with you, they're probably playing chords that support and enhance the melody.

Different chords create different feelings. Some chords sound happy and bright (called major chords), while others sound sad or mysterious (called minor chords). A chord progression is when musicians move from one chord to another in a pattern, creating the emotional journey of a song.

Don't confuse chord with cord, which means rope or wire: you play a chord on your guitar, but you plug in your guitar with an electrical cord.