Chapter Summary

Two or more different tones sounded together produce harmony. A chord is a meaningful combination of three or more tones sounded simultaneously. The most common chord in Western music is the triad. Chords may be relatively consonant or dissonant, depending upon the degree of tension or activity their sound suggests.

Tonality has been the prevalent harmonic system in the West since the early seventeenth century. In tonal music, each of the triads built upon the steps of the major or minor scale bears a specific relationship to the most important chord, the tonic. The next most frequently used chords are the dominant and subdominant triads.

There are three basic textures in music: monophony, polyphony, and homophony. Each is defined according to its predominantly melodic or harmonic conception.