A musical notation consisting of two vertical lines drawn close together, extending from the top to the bottom of the staff. It serves primarily to delineate sections within a composition or to signify the conclusion of a piece or a significant portion thereof. One type indicates the end of a section, while another, bolder type signals the absolute end. Examples of usage include marking the end of a verse, chorus, or bridge in a song, or separating distinct movements in a larger work.
The employment of this notation provides visual clarity for performers, assisting in navigation through the score and understanding the structure. It aids in rehearsing by providing easily identifiable points of reference. Historically, its use has evolved along with musical notation itself, becoming a standardized element across diverse genres and periods. Its presence enhances both the readability and the interpretability of musical scores.