The most general word musicians use to refer to the sounding at the same time of different pitches is harmony. The folk singer’s melody is said to be harmonized. She uses a number of standard groupings of simultaneous pitches that work well in combination. These groupings are called chords. The changing chords provide a shifting sound background for the melody. Any melody can be harmonized in different ways using different chords, and the overall effect of the music depends to a great extent on the nature of these chords, or the harmony in general.

In most of the music we hear, harmony is almost as important an element as melody. And, like melody, harmony is a powerful stimulus to our emotional responses to music.