The most common type of chord is a triad, which is a combination of three notes. Triads can be major, minor, augmented, or diminished, and they can be used to create a variety of different harmonic effects. For example, major chords sound bright and cheerful, while minor chords sound dark and sad.
Other types of chords include seventh chords, ninth chords, and eleventh chords. These chords are all made up of more than three notes, and they can create a more complex and interesting harmonic sound.
Chords are used in all types of music, from classical to jazz to rock. They are an essential part of music theory and composition, and they can be used to create a wide variety of different musical effects.