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.

X

xerography

From the Greek xeros and graphos, meaning "dry writing." A method of reproducing text and/or images in which dry resinous toner transferred from an electrostatically charged plate is thermally adhered to a sheet of paper or some other copying surface inside a photocopier (originally called a xerox machine). The result is a photocopy or xerox copy. Xerography is a form of reprography. Click here to learn more about how xerography works, courtesy of HowStuffWorks.

x-height

The mean height of the lowercase letters of a typeface that have neither ascenders nor descenders, sometimes used instead of point size as an indication of type size. The x-height letters of the roman alphabet are: a, c, e, m, n, o, r, s, u, v, w, x, and z. The tops and bottoms of some letters such as the "c" and "o" may extend slightly above the mean line and below the base line. Also spelled ex-height. See also: primary letter.

XML

See: Extensible Markup Language.

x-patent

See: patent.

XR

See: returns.

x-rated

A motion picture or videorecording containing material considered suitable for adults only, usually because it contains material considered pornographic. The term is also applied to print publications containing adult material (magazines, photographs, etc.). See also: unexpurgated.

x-ref

See: cross-reference.

XSL

See: Extensible Stylesheet Language.

XVGA

See: SVGA.

xylograph

Text and/or image printed from a woodblock. The blockbooks of the 15th and 16th centuries are a prime example. Xylographic illustration was also used in manuscripts and press-printed books of the same period, sometimes hand-tinted. Click here to see woodcut illustration in a Book of Hours printed in 1503 (Cornell University Library). See also: chiro-xylographic.

xylography

Printing done from blocks of wood, especially by the early process of wood engraving, concurrent with the early development of printing from movable type. The results, known as xylographica, often contain more illustration than text. See also: blockbook and woodcut.