information about the relationship between the parts that make up a compound object
NISO/IMLS 2007, 58Structural metadata documents relationships within and among objects and enables users to navigate complex objects, such as the pages and chapters of a book.
NISO/IMLS 2007, 83Structural metadata relates the pieces of a compound object together and/or bundles related objects into a package. For example, if a book is digitized as individual page images, structural metadata can record information concerning the order of files (page numbering) and how they relate to the logical structure of the book (table of contents) is also required.
Puglia, Reed, and Rhodes 2004, 10Structural metadata might include whether the resource is simple or complex (multi-page, multi-volume, has discrete parts, contains multiple views); what the major intellectual divisions of a resource are (table of contents, chapter, musical movement); identification of different views (double-page spread, cover, detail); the extent (in files, pages, or views) of a resource and the proper sequence of files, pages and views; as well as different technical (file formats, size), visual (pre- or post-conservation treatment), intellectual (part of a larger collection or work), and use (all instances of a resource in different formats—TIFF files for display, PDF files for printing, OCR files for full text searching) versions.