In music, a barre chord (also known as bar chord or rarely barr chord) is a type of chord on a guitar or other stringed instrument, that the musician plays by using one or more fingers to press down multiple strings across a single fret of the fingerboard (like a bar pressing down the strings).
Players use this chording technique to play a chord that is not restricted by the tones of the guitar's open strings. For instance, if a guitar is tuned to regular concert pitch, with the open strings being E, A, D, G, B, E (from low to high), open chords must be based on one or more of these notes. To play an F♯ chord the guitarist may barre strings so that the chord root is F♯.
Barre chords are sometimes called "moveable" chords, as the player can move the whole chord shape up and down the neck. Commonly used in both popular and classical music, Barre chords are frequently used in combination with "open" chords, where the guitar's open (unfretted) strings construct the chord. Playing a chord with the barre technique slightly affects tone quality. A closed, or fretted, note sounds slightly different sound than an open, unfretted, string. Barre chords are a distinctive part of the sound of pop music and rock music.
Using the barre technique, the guitarist can fret a familiar chord that is usually played with open strings, and then transpose, or raise, the chord a number of half-steps higher, similar to the use of a capo. For example, if a guitarist plays an E major and wants the next chord to be an F♯ Major—barring the open E major up two frets (thus two semitones) from the open position produces a barred F♯ Major chord.