Definition of a Chord
In music theory, a chord is a harmonic set of pitches consisting of three or more notes played simultaneously. These notes combine to create a sense of consonance or dissonance, forming the foundation of musical harmony. Unlike a single note or interval, a chord provides depth and texture in compositions.
Structure of Chords
Chords are typically built by stacking intervals, most commonly thirds, starting from a root note. The basic triad includes the root, third, and fifth degrees of a scale. Variations arise from the quality of the third (major or minor) and additional notes, such as the seventh, which extend the chord's complexity and emotional impact.
Practical Example: The C Major Chord
Consider the C major chord, formed by the notes C (root), E (major third), and G (perfect fifth). Played together on a piano or guitar, these notes produce a bright, stable sound. In a key of C major, this chord often appears as the tonic, resolving tension in a musical phrase.
Importance of Chords in Music
Chords are crucial for establishing tonality, supporting melodies, and evoking emotions in genres from classical to pop. They enable progressions that drive song structure, such as the common I-IV-V pattern, and are applied in analysis, composition, and performance to enhance musical expression.