In music for stringed instruments, especially guitar, an open chord (open-position chord) is a chord that includes one or more strings that are not fingered. Thus in an open chord the strings ring, or sound, freely and fully. In contrast, all of the strings are fingered for a barre chord. Guitarists use capos, which are devices that clamp down the strings to create a movable nut, to play open chords in different keys. With a capo on the first fret, an open A minor chord would sound like a Bb minor chord.
In guitar music, open chords are also called cowboy chords owing to their simplicity and reminiscence of a "cowboy strummin' away on the prairie."Malcolm Young of AC/DC is particularly well known for his use of open-position chords.