Leaf (books) in the context of "Folio"

The term "folio" (from Latin folium 'leaf') has three interconnected but distinct meanings in the world of books and printing: first, it is a term for a common method of arranging sheets of paper into book form, folding the sheet only once, and a term for a book made in this way; second, it is a general term for a sheet, leaf or page in (especially) manuscripts and old books; and third, it is an approximate term for the size of a book, and for a book of this size.

First, a folio (abbreviated fo or 2) is a book or pamphlet made up of one or more full sheets of paper, on each of which four pages of text are printed, two on each side; each sheet is then folded once to produce two leaves. Each leaf of a folio book thus is one half the size of the original sheet. Ordinarily, additional printed folio sheets would be inserted inside one another to form a group or "gathering" of leaves prior to binding the book.

Papyrus 46, also known as P. Chester Beatty II, is an early Greek New Testament manuscript written on papyrus, and is one of the manuscripts comprising the Chester Beatty Papyri. It is designated by the siglum 𝔓 in the Gregory-Aland numbering of New Testament manuscripts. Manuscripts among the Chester Beatty Papyri have had several provenances associated with them, the most likely being the Faiyum. Using the study of comparative writing styles (palaeography), it has been dated to between 175 and 225, or to the early 3rd century CE. It contains verses from the Pauline Epistles of Romans, 1 Corinthians, 2 Corinthians, Galatians, Ephesians, Colossians, Philippians, 1 Thessalonians, and Hebrews. Some leaves are part of the Chester Beatty Biblical Papyri, and others are in the University of Michigan Papyrus Collection.

In November 2020, the Center for the Study of New Testament Manuscripts (CSNTM) in conjunction with Hendrickson Publishers released a new 1:1 high-resolution imaged facsimile edition of 𝔓 on black and white backgrounds, along with 𝔓 and 𝔓.

A signature mark, in traditional bookbinding, is a letter, number or combination of either or both, which is printed at the bottom of the first page, or leaf, of a section.

The section is itself referred to as a signature, also called collation or gathering.