The Happy Anatomy of a Major Chord

Description

Let's stick with the C major chord, in open position.

We can play the major triad, the C, E, and G all at once, on the 5th, 4th, and 3rd strings.

But the C chord also includes the 2nd and first strings, right?
So what are those notes?

The 2nd string, as fingered in the C chord, is another C!
The 1st string, left open in the C chord, is another E!
So it's just duplicates of the notes from the original recipe, played in a higher octave.

It's all C's, E's, and G's. Nothing else.

So that is the major chord in action. At its core, it is a major triad. Notes 1, 3, and 5. But those notes can repeat themselves on other strings, in any order, and it will still add up to a major chord.