Figured bass is musical notation in which numerals and symbols appear above or below a bass note. The numerals and symbols indicate intervals, chords, and non-chord tones that a musician playing piano, harpsichord, organ, or lute should play in relation to the bass note. Figured bass is closely associated with basso continuo: a historically improvised accompaniment used in almost all genres of music in the Baroque period of Classical music, though rarely in modern music. Figured bass is also known as thoroughbass.

In music, a chord is a group of three or more notes played simultaneously, typically consisting of a root note, a third, and a fifth. Chords are the building blocks of harmony and form the harmonic foundation of a piece of music. They can be major, minor, diminished, augmented, or extended, depending on the intervals between the notes and their arrangement. Chords provide the harmonic support and coloration that accompany melodies and contribute to the overall sound and mood of a musical composition. For many practical and theoretical purposes, arpeggios and other types of broken chords may also be considered as chords in the right musical context.