The term describes a publication format where pages are not permanently bound together. Instead, individual sheets are held in place by rings, posts, or other mechanisms that allow for easy removal, re-arrangement, and addition of pages. A common example is a three-ring binder containing paper sheets with corresponding holes.
This design facilitates customization and updating. Professionals often employ this format for training manuals, presentations, or reference materials that require frequent revisions. Students also find this flexible approach useful for organizing notes, incorporating handouts, and creating personalized study guides. Historically, this binding method offered an alternative to traditional bookbinding, enabling dynamic content management not possible with fixed-page formats.