To fold the corner of a book's page.
(of a page in a book) Bent or slightly ragged in appearance, especially due to having been read many times.
The pages in his favorite book were dog-eared from years of reading it at bedtime.
(of a page in a book) Having the corner folded over, as a sort of bookmark.
By thumbing to the dog-eared pages, she quickly found the items in the catalog she wanted to order.