encyclopedia

American  

[en-sahy-kluh-pee-dee-uh] / ɛnˌsaɪ kləˈpi di ə /

Sometimes encyclopaedia

noun

• encyclopedias
  plural

1. a book, set of books, optical disc, mobile device, or online informational resource containing articles on various topics, usually in alphabetical arrangement, covering all branches of knowledge or, less commonly, all aspects of one subject.

2. Encyclopedia, the French work edited by Diderot and D'Alembert, published in the 18th century, distinguished by its representation of the views of the Enlightenment.

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encyclopedia British  

/ ɛnˌsaɪkləʊˈpiːdɪə /

noun

1. a book, often in many volumes, containing articles on various topics, often arranged in alphabetical order, dealing either with the whole range of human knowledge or with one particular subject

   a medical encyclopedia

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Other Word Forms

Noun Inflected Forms

• encyclopedias
  plural

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Etymology

Origin of encyclopedia

First recorded in 1525–35; from New Latin encyclopaedia, from Greek enkyklopaidía, a misreading of enkýklios paideía “circular (i.e., well-rounded) education”; see encyclical, pedo- ¹

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Explanation

An encyclopedia is a reference work designed to cover all branches and topics of knowledge. We might describe someone who seems to know everything as a "walking encyclopedia." Encyclopedia comes the Greek words for "comprehensive" (cyclo) and "education" (pedia). The first encyclopedias were books (usually in many volumes), but now we have online and electronic encyclopedias. This reference is usually organized alphabetically and covers as many topics as possible. If you're doing research, the encyclopedia is a good place to start.

Example Sentences

See Examples For:

encyclopedia encyclopedias

"For an encyclopedia it's different. Wikipedia runs on trust. A wrong fact can sit there for years and get cited by journalists and AI systems," he says.

From BBC ● Oct. 13, 2026

He is an encyclopedia of knowledge on high school sports, and his ideas about keeping this level of competition moving in the right direction is unmatched.

From Los Angeles Times ● Aug. 29, 2026

“We’re a bunch of nerds who write an encyclopedia as a hobby,” he said.

From The Wall Street Journal ● Jun. 10, 2026

Did everyone routinely use the encyclopedia, or read the Steinbeck novel, or listen attentively to Schubert’s Unfinished Symphony?

From Salon ● Apr. 19, 2026

Gilly shoved and pushed and tugged the heavy chair to a place opposite the red encyclopedia.

From "The Great Gilly Hopkins" by Katherine Paterson

Physical encyclopedias and textbooks were rendered virtually useless.

From Salon ● May 30, 2026

Samantha said Max has watched all of Sir David's documentaries and owns more animal encyclopedias than she can keep track of.

From BBC ● May 7, 2026

The chatbots also appeared conflicted about what role to play, shifting between acting like medical encyclopedias, life coaches and supportive friends.

From The Wall Street Journal ● Nov. 20, 2025

I loved reading books about dogs as a kid, whether they were encyclopedias of breeds or classics like “Hank the Cowdog.”

From Los Angeles Times ● Jul. 22, 2025

A clerk sat at the desk, between two tall piles of encyclopedias.

From "The Invention of Hugo Cabret" by Brian Selznick

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