folio

noun (plural folios)

• 1an individual leaf of paper or parchment, either loose as one of a series or forming part of a bound volume, which is numbered on the recto or front side only.
• the page number in a printed book.

• 2a sheet of paper folded once to form two leaves (four pages) of a book.
• a size of book made up of folio sheets of paper.
• a book or manuscript made up of folio sheets of paper; a volume of the largest standard size.