The use of half titles dates from the 17th century and may have evolved from the practice of including a blank leaf to protect the title page from wear. In modern printing, the half title helps the printer identify the work to which the first sheet belongs. In some editions, the half title also appears on the recto of a leaf separating the front matter from the first page of the text. Also spelled half-title. Synonymous with bastard title and fly-title.

In motion picture film and videotape, the beginning of a roll wound on a reel or core, as opposed to its end (the tail). Film intended for projection is wound head out.

Originally, the headband and tailband were a part of the sewing of a book, holding the sections together securely, but because they prevented the edges of the sections from being trimmed after sewing, their primary function was transferred to the kettle stitch, and endbands began to be glued on with the lining. On early bindings, the headbands were laced into the boards, and in fine binding they may still be embroidered for decorative effect. Compare with headcap.

Also refers to a decorative band printed at the top of a page or at the beginning of a chapter in older books. Synonymous in this sense with headpiece and head ornament.

In Dewey Decimal Classification (DDC), a word or phrase used as a description of a class, given in the schedules in conjunction with the class number, for example, "Library and information sciences" for which the class notation is 020.

Also, a line of type printed on a separate line at the beginning of a section of text in a chapter or other division of a work, to indicate the following content in a few descriptive words, usually distinguished from the text typographically (larger type size, boldface, italic, etc.).

Also refers to a uniform line of type printed at the top of the page in a book, giving the page number and running title, usually on the verso, or the chapter title or subject of the chapter or page, usually on the recto. Synonymous in this sense with page head and running head.

700 The Arts

720 Architecture

725 Public structures

725.8 Recreation buildings

725.82 Buildings for shows and spectacles

725.822 Theaters and opera houses

In an indexing language, logical hierarchy is indicated in the list of subject headings or thesaurus of descriptors by the codes BT (broader term) or NT (narrower term). In a more general sense, the arrangement of a set of terms or items by degree of specificity according to a given characteristic, for example, the sequence United States - New England - Massachusetts - Boston - Beacon Street, according to geographic location. See also: tree structure.

In a more general sense, any form of written expression that is difficult to read or understand.

Highlighting is also used in some computer applications to edit text by positioning the cursor at the beginning of a word, phrase, or entire passage, holding down the mouse button, and dragging the cursor to the end of the desired portion of text.

Also refers to a narrow cloth or paper stub inserted along the binding edge between the pages of a book to allow a map or added leaf to flex easily when the volume is opened. Synonymous in this sense with guard.

On the Internet, the number of times a given site is visited during a designated period of time, which can be recorded by an automatic counter supported by the software running the site.

In a narrower sense, all the copies, volumes, issues, or parts of an item owned by a library, especially a serial publication, indicated in a holdings statement in the record representing the item in the catalog. Holdings can be recorded in the MARC 21 Format for Holdings Information. See also: closed entry and open entry.

Also refers to a three-dimensional image of an object recorded on photosensitive film by the pattern of interference made by a split laser beam in a process called holography. Click here to learn more about holography.

To humidify is to put moisture into the atmosphere, usually done with a device called a humidifier to prevent paper documents from becoming brittle. Dehumidification takes moisture out of the atmosphere. It is done with desiccants or a dehumidifier to prevent mildew, warping, etc. Measured by an instrument called a hygrometer, humidity is carefully controlled in areas where archival and special collections are stored and used.