What does encyclopedia mean?
An encyclopedia is a reference work designed to gather human knowledge into organized, accessible form. Traditionally published as large multi-volume sets of alphabetically arranged articles, encyclopedias today are more often digital resources updated continuously online. Each entry offers a summary of a topic — a historical event, scientific concept, place, or person — giving readers reliable background information rather than the word-level focus of a dictionary. The word carries connotations of thoroughness and breadth: describing someone as 'a walking encyclopedia' praises the impressive range of their knowledge. Derived from Greek roots meaning roughly 'well-rounded education,' the term itself embodies the Enlightenment ideal that all learning could be collected and shared. From household print editions to collaborative online projects, the encyclopedia remains a symbol of organized, trustworthy knowledge available to anyone curious enough to look something up.
A book, set of volumes, or online resource containing informative articles on a wide range of subjects or on every aspect of one field, usually arranged alphabetically.
"The library's encyclopedia of world history filled an entire shelf."
Commonly used figuratively for a person with vast knowledge, often in the phrase 'a walking encyclopedia.'
(Informal) A person who has an exceptionally extensive store of knowledge across many subjects.
"My uncle is an encyclopedia when it comes to classic films."
Informal and complimentary; frequently intensified as 'walking encyclopedia.'
Standard regular plural. When referring to a multi-volume work treated as one unit, it may take a singular verb ('the encyclopedia is'), while the plural refers to multiple distinct works.
"Several encyclopedias were consulted before the article was published."
The word comes from Greek meaning 'all-around education' — the original encyclopedia wasn't a book at all, but the complete circle of knowledge a well-educated person was expected to master.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of encyclopedia
'Encyclopedia' derives from the post-classical Greek phrase 'enkuklios paideia,' meaning 'general' or 'all-round education' — literally instruction within a circle, suggesting a complete course of learning. The phrase passed into Latin as a mistaken reading of two separate Greek words as one, and the modern term entered English in the early modern period, with the spelling 'encyclopaedia' preserving its Greek roots in British usage. It shares the Greek root 'kyklos' (circle) with words such as 'cycle' and 'encyclical.'
Related word forms
How encyclopedia is actually used
The British spelling 'encyclopaedia' reflects the word's Greek origin via Latin, while American English prefers 'encyclopedia'; both are fully standard in their respective regions. In informal speech, calling someone 'an encyclopedia' or 'a walking encyclopedia' is a warm compliment about their knowledge, never an insult.
Easily confused with encyclopedia
A dictionary defines individual words and their meanings, while an encyclopedia provides in-depth articles about topics, people, events, and fields of knowledge.