Definition of "folio"

[Thomas] Hood also presented his treatises in such a way that conveniently accessing specific lessons was difficult, if not impossible, for the reader-practitioner. For example, his book entitled The Vse of Both the Globes, Celestiall and Terrestriall... (1592) was roughly two hundred pages long but did not include such helpful tools as an index, a table of contents, or even folio numbers. In order to refer to some lesson that he might need, the reader would have to leaf through the text until the passage in question was found, or else rely upon his own marginal notes.

2004, Eric H. Ash, “Secants, Sailors, and Elizabethan Manuals of Navigation”, in Power, Knowledge, and Expertise in Elizabethan England, Baltimore, Md., London: Johns Hopkins University Press, page 162

We saw above that the fourth quire consists of ten folios, two of which (folios 29 and 31) Richer added to a quaternion (folios 23 to 28, 30, 32). Most of the folios Richer added to his manuscript supplement, elaborate, or amend text that he had already composed in the codex. In this quire, however, Richer wrote around the added folios as if it was the quire he added to them, not the converse. Indeed, if we were to remove folios 29 and 31, there would be neither grammatical nor narrative continuity between the original folios of the quire which would face each other, that is, between folios 28v[erso] and 30r[ecto] on the one hand, or folios 30v and 32r on the other.

2004, Jason Glenn, Politics and History in the Tenth Century: The Work and World of Richer of Reims, Cambridge: Cambridge University Press, page 140

Folio Page.—A page which occupies the half of a full sheet of paper, as Post-folio, Demy-folio, etc. Two pages of folio are imposed together as one form, four pages being a perfect sheet. Post-folio and Foolscap-folio, however, are more frequently imposed as four-page forms, and printed on Double-post and Double-foolscap paper.]

Luther Ringwalt, editor, American Encyclopædia of Printing, Philadelphia, Pa.: Menamin & Ringwalt, 517 Minor Street; J. B. Lippincott & Co., 715 Market Street, page 172

In the leger,[sic] articles of the ſame kind are collected together; and, for that purpoſe, it is divided into many accounts, under which the different branches of buſineſs are arranged. Each account is introduced by a proper title, to explain the nature of the articles it contains; and articles of oppoſite kinds, which belong to the ſame account, are placed on the oppoſite pages of the ſame folio: for inſtance, money received on the one ſide, and money paid on the other; or goods bought on the one ſide, and goods ſold on the other.

1806, “Book-keeping”, in The New and Complete American Encyclopædia: or, Universal Dictionary of Arts and Sciences; [...] In Seven Volumes, volume II, New York, N.Y.: Printed and published by John Low, No. 33, Chatham-Street, page 152

When actions are brought in the Courts of King's Bench or Common Pleas, founded upon original writs issuing out of the Courts of Chancery (which writs, as stated in the Report of the 9th of April 1816, it is the duty of the Cursitors to make out) it has been the practice in certain cases for the Filacers of the Courts of King's Bench and Common Pleas respectively, to receive from the Suitors the King's fines (if any) and also the fees payable to the Cursitors in respect of such original writs, and afterwards to account to the Cursitors for the fines and fees so received. […] The Cursitors have claimed before us a right to compute the skin in all cases, at twenty folios, each folio containing seventy-two words; and to charge 1 s. 4 d. for every folio, instead of the fees now taken per folio or per skin, where the writ in charged in that manner. In support of this claim they have contended, that twenty folios of seventy-two words each, were established by the Order of 1743, as the length of a skin; […] The writ [of Transgress' super Casum], exclusive of the part containing the matter of the declaration, contains less than two folios of seventy-two words each; common counts are stated to contain usually, from two to three folios; special counts are usually longer, and sometimes of a much greater length.

1817 December 20, House of Commons of the United Kingdom, “Second Report of the Commissioners for Examining into the Duties, Salaries and Emoluments, of the Officers, Clerks and Ministers, of the Several Courts of Justice, in England, Wales, and Berwick-upon-Tweed;—as to the Court of Chancery”, in Reports from Committees: Fever; Ireland; Courts of Justice: Session 27 January – 10 June, 1818, volume VII, [London]: [s.n.], published 6 April 1818, pages 172 and 176

If the office copy of a Will or any part of a Will or other document is required to be made fac-simile, and such Will or part of a Will or other document is two folios of ninety words in length or under, in addition to the fee for the copy … … … … [£]0 1[s.] 0[d.] / If exceeding two folios of ninety words, for every additional folio or part of a folio … … [£]0 0[s.] 6[d.]

1862, George Henry Cooper (reporter), Alexander Staveley Hill (reporter), “Fees to be Taken in the Principal Registry of the Court of Probate in Non-contentious Business”, in The Law Journal Reports for the Year 1862: Cases in the Court of Probate, in the Court for Divorce and Matrimonial Causes, and in the High Court of Admiralty (New Series; XXXI), volume XL, part IV, London: Printed by James Holmes, 4, Took's Court, Chancery Lane; published by Edward Bret Ince, 5, Quality Court, Chancery Lane, page 64

And all the pleadings and other proceedings and copies thereof shall be fairly and legibly written; and if not so written, and folioed, and indorsed as aforesaid, the clerks shall not file such as may be offered to them for that purpose, nor will the court hear any motion or application founded thereon.

1860, Nathan Howard, Jr., “Rules of the Supreme Court”, in The Code of Procedure of Pleadings and Practice of the State of New-York, 1860, 2nd enl. and improved edition, New York, N.Y.: Banks & Brothers, law publishers, 144 Nassau Street; and 475 Broadway, Albany, rule XX, page 735

Folioing. The rule previously stated as to affidavits and other papers in respect to folioing applies also to petitions. They must be fairly and legibly written and indorsed, and where they are of more than two folios in length must be folioed.

1874, William Wait, “Part XIII. Motions, Orders and Papers. Chapter II. Affidavits and Petitions. Article II. Petitions. Section 3. Form and Contents of Petitions.”, in The Practice at Law, in Equity, and in Special Proceedings, in All the Courts of Record in the State of New York; with Appropriate Forms, volume IV, Albany, N.Y.: William Gould & Son, law booksellers and publishers, page 585

Folioing is necessary as an indication how far in his work the poster has proceeded, and must be done in both books immediately after each entry.

1907, J[ohn] Thornton, “Lesson VII.—The Principle of the Transfer from Preparatory to Final Record”, in A Manual of Bookkeeping for the Use of Students (Elementary Commercial Class-books), new and rev. edition, London: Macmillan and Co., Limited, St Martin's Street, London, page 105