What is the definition of chord progression?

In music, a chord progression is a series or sequence of chords. In Western music, chord progressions are most commonly used in tonal music, where they provide a sense of structure and harmonic movement. A chord progression can be as short as two chords or as long as several hundred chords.

Chord progressions can be used to create a variety of musical effects. For example, a simple I-IV-V-I progression (also known as a "perfect cadence") creates a sense of resolution, while a more complex progression like I-vi-IV-V-I (known as a "plagal cadence") can create a more unsettled feeling. The harmonic color of a chord progression can also be used to create different moods or atmospheres in music.

In modern music, chord progressions are often used in popular, jazz, and classical music. They can be found in a wide variety of songs and pieces, from simple folk songs to complex symphonies.