A major 6th chord

What each note does

• A is the root. It names the chord and is the note your ear hears as home.
• C♯ is the major third. It makes the chord sound bright. Lower it a half step to C and the chord turns minor.
• E is the fifth. It adds weight without changing the character, so it is the first note to drop when a voicing gets crowded.
• F♯ is the sixth, a softer color than a seventh. It adds sweetness without tension.