folionoun/ˈfəʊlɪəʊ/

• 1

  A leaf of a book or manuscript.

  • [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.
  • 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 28^(v[erso]) and 30^(r[ecto]) on the one hand, or folios 30ᵛ and 32ʳ on the other.
• 2

  A page of a book, that is, one side of a leaf of a book.

  • 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.
• 3

  mediaprintingpublishingA page number. The even folios are on the left-hand pages and the odd folios on the right-hand pages.

  • Folio.—The running number of the pages of a work. When there is no running title, the folio is placed in the centre of the head-line; when there is a running title, at the outside corner—the even folio on the left, the odd on the right. The preface, contents, index, and all introductory matter, usually have separate folios inserted in Roman lower-case numerals.
  • verso left-hand page of a book usually identified with even folio numbers. […] recto right-hand page of a book usually identified with odd folio numbers.
• 4

  mediaprintingpublishingA sheet of paper folded in half.

  • This pocket copying-machine, by which letters and writings of all sizes, even folio, may be very quickly copied, consists of a press four inches long, with a small cylinder, which contains pens and ink: the whole apparatus may be conveniently carried in the pocket, and the price is very moderate.
• 5

  mediaprintingpublishingA 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.
  • A treatiſe in Folio, intitled, The Magazen of Honour, or a Treatiſe concerninge the Nobillitie of England accordinge to the Lawes of England, with their Priviledges in Parliament, & in what caſes noe priviledge, together with the Etymologie, definition & antiquitie of 3 ſortes of Barons.
• 6

  A wrapper for loose papers.

• 7

  accountingbusinessfinanceA page in an account book; sometimes, two opposite pages bearing the same serial number.

  • 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.
• 8

  computingengineeringmathematicsA protective case with a flap that folds to cover the screen of a mobile device.

folioverb/ˈfəʊlɪəʊ/

• 1

  To put a serial number on (a folio or page, or on all the folios or pages of a book); to foliate, to page.

  • 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.
  • 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.