Encyclopædia

Encyclopædia is a reference work designed to summarize knowledge on a wide range of topics. Typically, it presents articles that cover science, history, culture, and other subjects, often arranged alphabetically and complemented by illustrations, maps, and cross-references. The term in this ligatured form is a historic spelling variant of encyclopedia and is seen in the official names of some long-standing reference sets.

Etymology and usage ensue from the Greek enkyklopaideia, meaning “a circle of learning” or “instruction for a circle,” formed from enkyklos “circle” and paideia “education.” The word was transmitted through Latin as encyclopaedia and into English. The ligature æ in Encyclopædia reflects traditional typography; today the form encyclopedia is more common in American practice, while some titles and publishers retain Encyclopædia or the ligature in branding.

History and development begin with ancient and medieval precursors such as Isidore of Seville’s Etymologiae and Vincent of Beauvais’s Speculum Majus, which assembled known knowledge for educational purposes. The modern encyclopedic project crystallized in the 18th century with the Encyclopédie of Denis Diderot and Jean le Rond d’Alembert, a landmark in systematic, collaborative reference work. This model influenced numerous national and subject encyclopedias in the 18th to 20th centuries and laid groundwork for contemporary digital compendia.

Notable examples include Encyclopædia Britannica, founded in 1768 in Scotland, and other enduring titles such as Brockhaus Enzyklopädie and Larousse. In the digital era, encyclopedias extend to online and open-content platforms, with Wikipedia representing a major contemporary form alongside established paywalled and public-domain resources.