Encyclopædia, a name of Greek derivation, given to works which embrace within their pages a more or less complete account, in alphabetical order, of the whole round of human knowledge, or of some particular section of it. Attempts in this direction were made as far back as Aristotle's day, and various others have since been made from time to time, according as the circle of knowledge widened. Amongst famous encyclopædias which have appeared, mention may be made of the French “Encyclopédie” (q.v.); the “Encyclopædia Britannica,” Edinburgh (1708-1771), now in its ninth edition (1889); the German “Encyclopedie,” begun in 1818 by Ersch and Gruber, and not yet completed, although 170 volumes have appeared; while the largest of all is the Chinese encyclopædia, in 5020 vols., printed in Pekin in 1726.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Encyclical Letter * Encyclopédie