Encyclopedia vs. Cyclopaedia — Which is Correct Spelling?

A comprehensive reference work containing articles on a wide range of subjects or on numerous aspects of a particular field, usually arranged alphabetically.

An encyclopedia (American English), encyclopædia, or encyclopaedia (British English) is a reference work or compendium providing summaries of knowledge either from all branches or from a particular field or discipline. Encyclopedias are divided into articles or entries that are often arranged alphabetically by article name and sometimes by thematic categories.

A comprehensive reference work (often spanning several printed volumes) with articles (usually arranged in alphabetical order, or sometimes arranged by category) on a range of subjects, sometimes general, sometimes limited to a particular field.

(dated) The circle of arts and sciences; a comprehensive summary of knowledge, or of a branch of knowledge.

The circle of arts and sciences; a comprehensive summary of knowledge, or of a branch of knowledge; esp., a work in which the various branches of science or art are discussed separately, and usually in alphabetical order; a cyclopedia.

A reference work (often in several volumes) containing articles on various topics (often arranged in alphabetical order) dealing with the entire range of human knowledge or with some particular specialty