A "broken chord" is a chord broken into sequence of notes. A broken chord may repeat some of the notes from the chord and span one or more octaves.

An arpeggio (Italian: [arˈpeddʒo]) is a type of "broken chord" where the notes comprising a chord are played or sung in a rising or descending order. An arpeggio may also span more than one octave.

The word "arpeggio" comes from the Italian word "arpeggiare", which means "to play on a harp".

Even though the notes of an arpeggio are not played or sung all together at the same time, listeners hear the sequence of notes as forming a chord. When an arpeggio also contains passing tones that are not part of the chord, different music theorists may analyze the same musical excerpt differently.

Arpeggios enable composers writing for monophonic instruments that play one note at a time (e.g., flute, saxophone, trumpet), to voice chords and chord progressions in musical pieces. Arpeggios and broken chords are also used to help create rhythmic interest. A notable example of which is the Alberti bass figuration which was widely used in piano music from the Classical music period. With an Alberti bass, rather than play the notes of a chord all at once, the pianist plays simple rhythmic figures in which the notes of the chord are played as a broken chord.