capo
A clamp placed across the strings of a fretted instrument to raise the pitch of all strings simultaneously.
In Depth
A capo (short for capotasto, Italian for head of the fretboard) is clamped across the neck of a guitar, banjo, or similar instrument, effectively shortening all the strings and raising their pitch. This allows the player to use the same familiar chord shapes in a higher key without learning new fingerings.
Capos are essential tools for singer-songwriters who need to match a song to their vocal range. They also change the instrument's timbre — a capo placed high on the neck produces a brighter, more mandolin-like tone. Some guitarists, like Albert Collins and Keith Richards, are famous for their creative use of capos.
Keith Richards of the Rolling Stones uses a capo and removes the lowest string from his guitar, creating an open G tuning that defined the sound of songs like Start Me Up and Brown Sugar.