Title page of "Lucubrationes
..." 1541 edition, the first book to use the word encyclopedia in the title
encyclopedia comes from the
Koine Greek ἐγκύκλιος παιδεία,
 transliterated enkyklios paideia, meaning "general education" from enkyklios (ἐγκύκλιος), meaning "circular, recurrent, required regularly, general"
paideia (παιδεία), meaning "education, rearing of a child";
 it was reduced to a single word due to an error
 by copyists of
Latin manuscripts. Together, the phrase literally translates as "complete instruction" or "complete knowledge".
Indeed, the purpose of an encyclopedia is to collect knowledge disseminated around the globe; to set forth its general system to the men with whom we live, and transmit it to those who will come after us, so that the work of preceding centuries will not become useless to the centuries to come; and so that our offspring, becoming better instructed, will at the same time become more virtuous and happy, and that we should not die without having rendered a service to the human race in the future years to come.
Copyists of Latin manuscripts took this phrase to be a single Greek word, enkyklopaidia, with the same meaning, and this spurious Greek word became the
New Latin word "encyclopaedia", which in turn came into English. Though the notion of a compendium of knowledge dates back thousands of years, the term was first used in the title of a book in 1517 by
Johannes Aventinus: Encyclopedia orbisque doctrinarum, hoc est omnium artium, scientiarum, ipsius philosophiae index ac divisio, and in 1538 by
Joachimus Fortius Ringelbergius, Lucubrationes vel potius absolutissima kyklopaideia (
Title page of
Skalich's Encyclopaedia, seu orbis disciplinarum, tam sacrarum quam prophanarum, epistemon
from 1559, first to use the word encyclopaedia
as a noun in the title
The word encyclopaedia was first used as a
noun in the title of his book by the
Pavao Skalić in his Encyclopaedia seu orbis disciplinarum tam sacrarum quam prophanarum epistemon (Encyclopaedia, or Knowledge of the World of Disciplines, Basel, 1559). One of the oldest
vernacular uses was by
François Rabelais in his
Pantagruel in 1532.
 Several encyclopedias have names that include the suffix -p(a)edia, e.g.,
Banglapedia (on matters relevant for Bengal).
In British usage, the spellings encyclopedia and encyclopaedia are both current.
 In American usage, only the former is commonly used.
 The spelling encyclopædia—with the
ligature—was frequently used in the 19th century and is increasingly rare, although it is retained in product titles such as Encyclopædia Britannica and others. The
Oxford English Dictionary (1989) records encyclopædia and encyclopaedia as equal alternatives (in that order), and notes the æ would be obsolete except that it is preserved in works that have Latin titles.
Webster's Third New International Dictionary (1997–2002) features encyclopedia as the main headword and encyclopaedia as a minor variant. In addition, cyclopedia and cyclopaedia are now rarely used shortened forms of the word originating in the 17th century.