A major 7th 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.
• G♯ is the major seventh, a half step below the root. It makes the chord sound rich and settled rather than pushing anywhere.