A chord progression is a sequence of chords played in a piece of music. Chords are groups of notes that sound harmonious when played together. These progressions create the foundation for a song, influencing its mood and emotional impact. Common progressions, like the I-IV-V or ii-V-I, are widely used in various genres, including pop, rock, and jazz. Chord progressions can vary in complexity, from simple three-chord patterns to intricate sequences involving many chords. Musicians often use them to build tension, resolve musical phrases, and enhance the overall structure of a composition. Understanding chord progressions is essential for songwriting and music theory.