Section 6.1 Introduction to Triads
A triad consists of three notes stacked in consecutive thirds. A triad is also called a chord as well as a harmony. (Harmony also refers to chord progressions.)
The lowest note of a triad when it is stacked in thirds is called the root. The middle note is the third and the highest note of the triad is the fifth. (We will discuss inversions of triads later.)
There are four qualities of triads—augmented, major, minor, and diminished.
Major and minor triads are common, diminished triads are less common, and augmented triads are rare.