encyclopedia

American  

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

Sometimes encyclopaedia

noun

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.

---

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

---

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”; encyclical, pedo- ¹

Example Sentences

As a child, he came across a page in an encyclopedia featuring Neil Armstrong and the picture of an astronaut on the Moon from the 1969 Apollo mission.

From BBC • Apr. 2, 2026

“I found the encyclopedia at the Underground,” he explains, of the DuBois work that became central to “Blknws.”

From Los Angeles Times • Mar. 4, 2026

For nearly half-a-century, until he retired last month, Howard Silverblatt was the walking, talking encyclopedia of the S&P 500.

From The Wall Street Journal • Feb. 10, 2026

He maybe saw the idea of an A.I.-generated encyclopedia and wanted to be first to market.

From Slate • Nov. 17, 2025

I looked up Lindbergh in the encyclopedia, and sure enough, the answer was right in the caption of the photo.

From "Doing Time Online" by Jan Siebold