ODLIS — Online Dictionary for Library and Information Science by Joan M. Reitz Now available in print! Order a copy of the hardcover or paperback from Libraries Unlimited.

Z

Z39.50

A client-server protocol established as a NISO standard that allows the computer user to query a remote information retrieval system using the software of the local system and receive results in the format of the local system, often used in portal and gateway products to search several sources simultaneously and integrate the results. Click here to connect to the Web page on Z39.50 maintained by the Network Development & MARC Standards Office of the Library of Congress.

zero-base budgeting (ZBB)

Financial planning that starts from zero at the beginning of each new budget cycle, with no assumptions carried over from previous experience, a method used in both the public and private sectors. In ZBB, every expense must be justified in each new cycle.

zero growth

See: steady state.

z-fold

See: accordion fold.

zig-zag book

A book made by folding a continuous strip of paper backward and forward accordion-style (see this example). When the pages are sewn at the back fold, the strip is printed on one side only. When both sides are printed, the folds are left unsewn to allow the volume to be opened to its full length. This form of book is called an orihon when made from a manuscript or printed document originally produced as a roll. Also spelled zigzag book. Compare with concertina.

zig-zag guard

In binding, a continuous single-piece guard produced by folding a sheet of strong paper or linen accordion-style, used in photograph albums and other guard books, in large blankbooks for sewing the folios, and in conservation bookbinding for resewing the sections. Also spelled zigzag guard. Synonymous with continuous guard.

zincograph

A print made from an engraving or etching done on a zinc plate. Click here and here to see two late-19th-century hand-colored examples by Alfred Jarry, inspired by devotional woodcuts (Spencer Museum of Art).

zine

Derived from "fanzine" (a contraction of "fan magazine"), pronounced "zeen." The term came into use during the 1980s to refer to a small, low-circulation magazine or newspaper, self-published out of passion for the subject rather than for personal gain, usually produced with the aid of desktop publishing software and high-quality photocopy machines.

Zines represent the convergence of amateur publishing hobbyists, high school underground newspapers, the literary small press, political radicalism, and do-it-yourself popular culture. They are usually not available by subscription, often appear irregularly or infrequently, and may have a lifetime of only one or two issues. Some are available online via the World Wide Web. Selected zines are evaluated in the reference serial Magazines for Libraries. To learn more, see The Book of Zines or the article "Your Zine Tool Kit" by Jenna Freedman in the June 15, 2006 issue of Library Journal.

zip

To compress a data file using PKZIP software or some other utility capable of compressing data into PKZIP format. When such a file is restored to an uncompressed format, it is said to have been unzipped.

Zip disk

A 3.5-inch removable magnetic disk cartridge developed by Iomega, capable of storing 100MB or more of data, much more than a standard floppy disk, at relatively low cost (see this example). A special Zip drive must be installed on a microcomputer to allow a Zip disk to be used.

Zip drive

A disk drive developed by Iomega that uses a 3.5-inch removable Zip disk capable of storing 100MB or more of data at relatively low cost, used for storing very large files and collections of files. The drive usually comes with software that catalogs the contents of the disk and provides file security.

Zipf's Law

The principle that the frequency of the rth most common word or phrase in a relatively lengthy text (or in any natural language) is approximately 1/r, with r equal to its statistical rank in frequency. This means that the 10th most frequent word will be used about twice as often as the 20th most frequent word, and ten times more often than the 100th most frequent word. Another way of stating Zipf's Law is that the frequency (P) of the rth most common word or phrase is P_r = 1/r ^a, with a close to 1 and for r up to about 1000 (the phenomenon breaks down for less commonly used words). Based on the observations of Harvard linguist George Kingsley Zipf (1902-1950), the relationship can also be stated in the equation r x f = k, where r is the rank of the word, f is its frequency, and k is a constant. Illustrating his point with an analysis of the text of James Joyce's Ulysses, Zipf found that the 10th most frequent word was used 2,653 times, the 100th most common word was used 265 times, and so on, yielding a constant of approximately 26,500. Although Zipf's Law is not a statistically accurate predictor, indexers find it helpful. Click here to learn more about Zipf's Law in Wikipedia.

zoo-anthropomorphic initial

A figure initial in a medieval manuscript or early printed book composed wholly or in part of one or more animal/human hybrids, often a human head on an animal body, or vice versa. Click here to see an example in an early 13th-century Bible (Schøyen Collection, MS 660). See also this illuminated initial "I" and this initial "S" in the form of hybrid creatures (British Library, Arundel 490 and 98). Zoo-anthropomorphic motifs also appear in inhabited initials, line fillers, and ornamental borders (Bodleian Library, MS Don.b.5). The Murthly Hours, written and illuminated in Paris in the 13th century, contains a large number of imaginative hybrid figures (National Library of Scotland). Compare with anthropomorphic initial and zoomorphic initial.

zoom

In photography, to alter the size of an image from a stationary camera position without changing perspective by using a zoom lens to increase or decrease the focal length. In cinematography, this type of lens appears to make the camera advance toward the subject when zooming in, or retreat from it when zooming out.

In word processing software, a feature that allows the user to enlarge or reduce the size of a page displayed on the screen, usually by a fixed percentage or in small increments. In Web browsers, a feature that allows the viewer to enlarge all or a portion of an image, sometimes in increments. Also, a feature on some photocopy machines that allows the user to specifiy the extent to which an original will be enlarged or reduced in size in copying.

zoomorphic initial

A figure initial in a medieval manuscript or early printed book composed wholly or in part of forms recognizable as animals or imaginary beasts. Zoomorphic initials are common in the Book of Kells. Click here to see a griffin in the the shape of an "S" in a 13th-century German psalter (Getty Museum, MS Ludwig VIII 2) and here to see an example in a 13th-century English Bible (Bodleian Library, MS Lat.bib.e.7). Click here and here and here and here to compare 11th- and 12th-century examples (courtesy of the British Library's Digital Catalogue of Illuminated Manuscripts) with this initial D in the 15th-century Hours of Dionora of Urbino (British Library, Yates Thompson 7) and this initial A in a 15th-century Italian antiphonal (Metropolitan Museum of Art). Zoomorphic motifs are also used in decorative line fillers, borders, and bas-de-page scenes. Compare with anthropomorphic initial and zoo-anthropomorphic initial.