A reference work is a compendium

Compendium

A compendium is a concise, yet comprehensive compilation of a body of knowledge. A compendium may summarize a larger work. In most cases the body of knowledge will concern some delimited field of human interest or endeavour , while a "universal" encyclopedia can be referred to as a compendium of...

 of information, usually of a specific type, compiled in a book for ease of reference

Reference

Reference is derived from Middle English referren, from Middle French rèférer, from Latin referre, "to carry back", formed from the prefix re- and ferre, "to bear"...

. That is, the information is intended to be quickly found when needed. Reference works are usually referred to for particular pieces of information, rather than read beginning to end. The writing style used in these works is informative; the authors avoid use of the first person, and emphasize facts. Indexes

Index (publishing)

An index is a list of words or phrases and associated pointers to where useful material relating to that heading can be found in a document...

 are commonly provided in many types of reference work. Updated edition

Edition

In printmaking, an edition is a number of prints struck from one plate, usually at the same time. This is the meaning covered by this article...

s are published as needed, in some cases annually

Annual publication

An annual publication, more often called simply an annual, is a book or a magazine, comic book or comic strip published yearly. For example, a weekly or monthly publication may produce an Annual featuring similar materials to the regular publication....

. Typical reference works include dictionaries, encyclopedias, and compendia (see further examples below). Many reference works are available in electronic form and can be obtained as software packages or online through the Internet

Internet

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

.

In comparison, a reference book or reference-only book in a library

Library

In a traditional sense, a library is a large collection of books, and can refer to the place in which the collection is housed. Today, the term can refer to any collection, including digital sources, resources, and services...

 is one that may only be used in the library and not borrowed from the library. Many such books are reference works (in the first sense) which are usually used only briefly or photocopied from, and therefore do not need to be borrowed. Keeping them in the library assures that they will always be available for use on demand. Other reference-only books are ones that are too valuable to permit borrowers to take them out. Reference-only items may be shelved in a reference collection located separately from circulating

Library circulation

Library circulation or library lending comprises the activities around the lending of library books and other material to users of a lending library. A circulation or lending department is one of the key departments of a library....

 items, or individual reference-only items may be shelved among items available for keeping.

Further reading

• Bergenholtz, H., Nielsen, S., Tarp, S. (eds.): Lexicography at a Crossroads: Dictionaries and Encyclopedias Today, Lexicographical Tools Tomorrow. Peter Lang 2009. ISBN 978-3-03911-799-4
• Sandro Nielsen: "The Effect of Lexicographical Information Costs on Dictionary Making and Use". In: Lexikos
  Lexikos
  Lexikos is a peer-reviewed academic journal in the field of lexicography, established in 1991. It is currently published by Bureau of the Woordeboek van die Afrikaanse Taal of the association the African Association for Lexicography. It became the official journal of the latter in 1996...
  
  18 (2008), 170-189.