What is an angle on a book on the corner of your page?

An angle on a book at the corner of your page refers to the geometric configuration formed by the intersection of two lines or edges that meet at that corner. In the context of a book, it typically describes the corner where the spine meets the cover or the pages, creating a right angle (90 degrees) or potentially other angles depending on the book's design. This corner can also influence how the book lays flat when opened or closed.