bar (music)

In musical notation, a bar or measure is a segment of time defined as a given number of beats of a given duration. The word measure is heard more frequently in the U.S., while bar is used in other English-speaking countries, although musicians generally understand both usages. The word bar derives from the vertical lines which separate one measure from another, and not the bar-like (i.e., rectangular) dimensions of a typical measure of music.
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