Iii Chord

Definition

The iii chord, or the mediant chord, is the third chord in a diatonic scale and is built on the third degree of the scale. This chord typically consists of a root, a major third, and a perfect fifth, creating a minor triad in a major key. Its role often includes providing a sense of contrast or color in harmonic progressions, making it an important embellishing tone within musical structures.

5 Must Know Facts For Your Next Test

1. In a major key, the iii chord is typically a minor chord, while in a minor key it can be either diminished or augmented.
2. The iii chord is often used as a transition between tonic (I) and dominant (V) chords, helping to create smoother harmonic movements.
3. This chord can also appear in deceptive cadences, where it substitutes for the expected dominant chord before resolving to the tonic.
4. The iii chord's role can enhance the emotional quality of music by providing contrast to other diatonic chords.
5. In jazz and contemporary music, the iii chord can serve as a pivot point for modulations or temporary tonicizations.

Review Questions

• How does the iii chord function within common chord progressions in major keys?
  • The iii chord functions as a bridge between the tonic (I) and dominant (V) chords within common progressions. It helps to create smooth transitions by connecting these two primary harmonies. Additionally, its placement can add color and depth to the overall sound, often leading to further movement towards either the dominant or back to tonic.
• Discuss how the iii chord contributes to harmonic variation and emotional expression in music.
  • The iii chord contributes to harmonic variation by offering contrasting colors compared to other diatonic chords. Its minor quality in a major key evokes different emotional responses and can create tension that enhances musical expression. By introducing this chord into progressions, composers can manipulate mood and drive the piece toward resolution or new sections.
• Evaluate the significance of using the iii chord in jazz harmonies compared to classical music practices.
  • In jazz harmonies, the iii chord holds significant importance as it often acts as a pivot for modulations and temporary tonicizations, allowing for fluid movement between keys. Unlike classical practices where it might serve a more decorative function, jazz utilizes the iii chord more dynamically within improvisation and complex progressions. This approach allows musicians to create richer textures and explore harmonic territories that transcend traditional tonal frameworks.

Related terms

Diatonic Scale:

A seven-note scale composed of five whole steps and two half steps, which forms the basis for most Western music.

Chord Progression:

A sequence of chords played in succession, creating a harmonic foundation for a piece of music.

Embellishing Tone: A non-harmonic tone that adds interest to a melody or harmony, often approached by step or leap.