Definition of "double bar" []

• Music A double vertical or heavy black line drawn through a staff to indicate the end of any of the main sections of a composition. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Purcell frequently set a double bar at the end of a section, and makes two or more numbers where a modern composer would simply change the tempo and key-signature and go straight on, so that the scrappiness is only apparent."