An encyclopedia or encyclopaedia (also spelled encyclopædia, see spelling differences) is a type of reference work or compendium holding a comprehensive summary of information from either all branches of knowledge or a particular branch of knowledge. Encyclopedias are divided into articles or entries, which are usually accessed alphabetically by article name. Encyclopedia entries are longer and more detailed than those in most dictionaries. Generally speaking, unlike dictionary entries, which focus on linguistic information about words, encyclopedia articles focus on factual information to cover the thing or concept for which the article name stands.
Encyclopedias have existed for around 2,000 years; the oldest still in existence, Naturalis Historia, was written starting in ca. AD 77 by Pliny the Elder; it was not fully revised at the time of his death in 79. The modern encyclopedia evolved out of dictionaries around the 17th century. Historically, some encyclopedias were contained in one volume, whereas others, such as the Encyclopædia Britannica, the Enciclopedia Italiana (62 volumes, 56,000 pages) or the world's largest, Enciclopedia universal ilustrada europeo-americana (118 volumes, 105,000 pages), became huge multi-volume works. Some modern encyclopedias, such as Wikipedia, are electronic and often freely available.
An encyclopedia is a book, or series of books, that contains general information about many topics and subjects. While often found with dictionaries in resource libraries, encyclopedias may be much longer and contain more information about the subjects within them. In the past, these works were collected in multiple published volumes. More modern publications, however, include digital formats such as software on a disc or websites with information on them.
Format and Purpose
Some people can confuse an encyclopedia with a dictionary, although they are inherently quite different. A dictionary offers definitions of words, occasionally accompanied by illustrations, to provide the reader with the meaning of individuals terms or phrases. On the other hand, an encyclopedia explores topics in greater depth and more often includes illustrations, maps, and photographs. While most encyclopedias are organized alphabetically, some are arranged by categories or cross-referenced articles to allow for easier reading.
Readers can find a wide range of subjects within these volumes, making them excellent research texts. Historical events, such as the dates and major battles of various wars; scientific information, like pertinent data regarding different theories; and popular culture, such as names and short biographies of various celebrities, can all be found in these volumes. As time goes on, publishers make revisions and release new volumes with more information, to keep them relevant.
Pliny the Elder wrote the first documented encyclopedia in the first century BC with the help of his nephew. This work consisted of 37 volumes and covered subjects ranging from anthropology and human physiology to agriculture, painting, and pharmacology. Through the following few centuries, encyclopedias adopted a religious overtone. The first Christian edition was published in 560 AD, and the first Muslim volume came to light soon after.
One of the longest encyclopedias ever was created in 1403 when the Yongle Encyclopedia was published in China. It consisted of 11,000 handwritten volumes; most of the original work has been lost through the centuries, and less than 400 volumes survive today. The word "encyclopedia" comes from the Greek enkyklia paideia, which means "a general knowledge." It has been in use for at least 500 years, since the publishing of Encyclopaedia, or Knowledge of the World of Disciplines in 1559.
In the 20th century, the Encyclopedia Britannica became the most well known western work of this type. Topical encyclopedias also came into popularity, covering topics as varied as economics,bioethics, or Judaica. Toward the end of the century, many publishers began releasing them in digital formats such as Compact Discs (CDs) and Digital Versatile Discs (DVDs).
Some encyclopedias have become entirely available online, with no corresponding print version. One of the most important advantages of online encyclopedias is that they can be edited frequently, so they remain up to date. Traditionally, a single writer wrote an encyclopedia alone or as a collaborative effort with peers, but a team of writers, who often have no face to face contact with each other, can now put together numerous volumes at a distance.