folio

1. A leaf of a book or manuscript.
2. A page of a book, that is, one side of a leaf of a book.
3. A page number. The even folios are on the left-hand pages and the odd folios on the right-hand pages.
4. A sheet of paper folded in half.
5. A book made of sheets of paper each folded in half (two leaves or four pages to the sheet); hence, a book of the largest kind, exceeding 30 centimetres in height. · A rare copy of Shakespeare’s First Folio.
6. A wrapper for loose papers.
7. A page in an account book; sometimes, two opposite pages bearing the same serial number.
8. A protective case with a flap that folds to cover the screen of a mobile device.

الجمع folios