The motivating question, which I quote at the beginning, was actually: what is a chord? what is a major chord? what is a note? what is a first/fourth/fifth note

The motivating question, which I quote at the beginning, was actually: what is a chord? what is a major chord? what is a note? what is a first/fourth/fifth note? is there a 65th note? what is a scale? what is a major scale? what does it mean that a note is of a scale? what does it mean that a chord uses a note? is there a difference between a chord using a note of a scale and not of a scale? I picked one of them for the title of my post, but I'm trying to answer them all.