Note that double bar refers not to a type of bar (i.e., measure), but to a type of bar line. Regular bar lines consist of a thin vertical line extending from the top line to the bottom line of the staff, sometimes also extending between staves in the case of a grand staff or a family of instruments in an orchestral score.Ī double bar line (or double bar) consists of two single bar lines drawn close together, separating two sections within a piece, or a bar line followed by a thicker bar line, indicating the end of a piece or movement.

The length of the bar, measured by the number of note values it contains, is normally indicated by the time signature. In musical notation, a bar (or measure) is a segment of music bounded by vertical lines, known as bar lines (or barlines), usually indicating one of more recurring beats.

For other uses, see Bar (disambiguation).