Definitions
1.NounA leaf of a book or manuscript.
2.NounA page of a book, that is, one side of a leaf of a book.
3.NounA page number. The even folios are on the left-hand pages and the odd folios on the right-hand pages.
A sheet of paper folded in half.
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."
4.NounA page number. The even folios are on the left-hand pages and the odd folios on the right-hand pages.
5.NounA sheet of paper folded in half.
6.NounA 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."
7.NounA wrapper for loose papers.
8.NounA page in an account book; sometimes, two opposite pages bearing the same serial number.
9.NounA protective case with a flap that folds to cover the screen of a mobile device.
10.NounA leaf containing a certain number of words; hence, a certain number of words in a piece of writing, as in England, in law proceedings 72, and in chancery, 90; in New York, 100 words. .mw-parser-output .defdate{font-size:smaller}
11.VerbTo put a serial number on (a folio or page, or on all the folios or pages of a book); to foliate, to page.