What is a chord in guitar music?

A chord is composed of 3 or more tones, typically. The interval between each tone determines the type of chord. For instance, a major chord is composed of 1, 3, and 5 (tones on the scale of the root, or 1, tone). A minor chord, on the other hand, is composed of 1, flatted 3, and 5. The C major chord is comprised of C, E, and G tones whereas the C minor chord is comprised of C, E minor and G tones.