While a chord is defined as a group of notes that are sounded together at the same time, an arpeggio, a.k.a. 'broken chord,' indicates a chord in which the notes are sounded individually.

Working on arpeggios will unlock the space between strumming chords and running scales, and give you a better general understanding of musical harmony-meaning, in its broadest sense, the ways that two or more notes can interact. As a rhythm guitarist, your playing will somehow sound both fuller and more specific. As a lead player, your solos will tell a more meaningful story by better matching the passing chords of the song or progression; think of a surfer who moves in and out of a wave's different sections instead of riding straight across its face.