Encyclopedias

An encyclopedia is a reference work that gathers summarized knowledge about many subjects, or about one subject in depth, and presents it in self-contained articles. Entries are usually arranged alphabetically by topic, though some works group articles by theme or field. Unlike a dictionary, which explains words, an encyclopedia explains the things, ideas, people and events that words denote, giving background, context and cross-references that link related articles.

Historically, encyclopedias were issued as multi-volume printed sets compiled by editors and subject experts. General encyclopedias aim to cover the whole field of human knowledge, while specialized encyclopedias concentrate on a single domain such as medicine, physics, philosophy, mythology, botany or religion. Many of the topics suggested for this page — technical and scientific subjects, etymology, stars and astronomy, herbal and medical knowledge, symbols, and world history — correspond to such subject-specific reference works.

The format changed greatly with electronic publishing. Online encyclopedias allow full-text searching, frequent updating, and hyperlinks between articles, and some are written collaboratively by large communities of contributors rather than a fixed editorial board. This makes a far wider range of entries available and keeps them current, but it also places more responsibility on the reader to check sourcing and accuracy. Encyclopedias remain a starting point for research: they give an overview of a topic, define its key terms, and point toward more detailed sources.

Frequently asked questions

How is an encyclopedia different from a dictionary?

A dictionary defines words, their spelling and usage. An encyclopedia explains subjects and concepts in fuller articles, with background and references to related topics.

What is a specialized encyclopedia?

It is a reference work limited to one field, such as medicine, physics or mythology, treating that subject in greater depth than a general encyclopedia would.

Are online encyclopedias reliable?

They can be, especially when articles cite sources. Because some are openly edited, readers should check citations and confirm important facts in additional references.