Definition of term:: Format

  • "This term (nowadays pronounced to rhyme with doormat) is defined by SOED as ‘the shape and size of a book’. In bibliographical contexts it is used to indicate the structure of a volume in terms of the number of times the original printed sheet has been folded to form its constituent leaves: modified when necessary by the subsequent make-up. Thus in a folio each sheet has been folded once, in a quarto twice, in an octavo three times; the size being thus respectively a half, a quarter and an eighth that of the original sheet. If the folded sheets have been gathered straightforwardly for sewing, then format will be indicated by a single term, e.g. quarto: if otherwise, the format of the completed volume will be expressed as, e.g. quarto in eights. (See gathering.) The methods of folding in books of the smaller sizes (especially 12mo and 24mo) have often varied and the bibliographical results are sufficiently complicated to drive most amateurs to mockerrow or gaskell, who elucidate most of them. But though the sizes of sheets vary substantially, thus producing subdivisions in the size of books, a terminology based on the method of folding has been found satisfactory for all but eccentrically shaped volumes. The principal formats, with their common abbreviations, are: Folio (Fo., of late years sometimes 2º). Quarto (Qto, 4to, 4º). Octavo (Oct., 8vo, 8º). Duodecimo (12mo, 12º, sometimes pronounced twelvemo). Sextodecimo (16mo, usually pronounced sixteenmo). Vicesimo-quarto (24mo, pronounced twentyfourmo) Tricesimo-secundo (32mo, pronounced thirtytwomo). It is the technical terms of the paper trade which provide the names – some, ‘median’ or ‘royal’, going back to the Middle Ages, others, such as pott and elephant deriving from water-marks as ancient – for the sub-categories of size. Most booksellers’ catalogues nowadays dispense with a terminology now unfamiliar to, and unnecessarily technical for, the majority of their readers. These know – or should know – that, from the early 17th century at least, a folio is a large upright-shaped volume and an octavo a small upright-shaped volume, while a quarto (between them in size) is essentially squarish in shape, the former generally with vertical chain lines, the latter with horizontal, although the use of double-size paper can reverse these effects. And where special precision is necessary – to distinguish between different issues or variants, or to establish a large paper copy – this is commonly effected by giving the measurements of the leaf (but see paper). Large folio, small folio, large quarto, small quarto are terms in constant use. But even the four traditional subdivisions of format – (downwards) royal, demy, crown, foolscap – are in practice almost never used for anything but 4to and 8vo. Foolscap is sometimes abbreviated to f ’cap. Demy is accented as in defy." (John Carter)
French: Format
German: Format
Swedish: Ark, arksignatur
Source: John Carter, ABC for Book Collectors. 7th edition. With Corrections, Additions and an Introduction by Nicolas Barker. Oak Knoll Press 1995