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.
Two Greek words misunderstood as one
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"; together, the phrase literally translates as "complete instruction" or "complete knowledge".
 However, the two separate words were reduced to a single word due to a scribal error
 by copyists of a
Latin manuscript edition of
Quintillian in 1470.
 The copyists 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. Because of this compounded word, fifteenth century readers and since have often, and incorrectly, thought that the Roman authors
Pliny described an ancient genre.
Title page of
Skalich's Encyclopaedia, seu orbis disciplinarum, tam sacrarum quam prophanarum, epistemon
from 1559, first clear use of the word encyclopaedia
in the title.
Sixteenth century usage of the compounded word
In the sixteenth century there was a level of ambiguity as to how to use this new word. As several titles illustrate, there was not a settled notion about its spelling nor its status as a noun. For example: Jacobus Philomusus's Margarita philosophica encyclopaediam exhibens (1508);
Johannes Aventinus's Encyclopedia orbisque doctrinarum, hoc est omnium artium, scientiarum, ipsius philosophiae index ac divisio;
Joachimus Fortius Ringelbergius's Lucubrationes vel potius absolutissima kyklopaideia (1538, 1541);
Encyclopaediae sen orbis disciplinarum epistemon (1559);
Gregor Reisch's Margarita philosophica (1503, retitled Encyclopaedia in 1583); and
Samuel Eisenmenger's Cyclopaedia Paracelsica (1585).
 It is only with
Pavao Skalić and his
Encyclopediae seu orbis disciplinarum tam sacrarum quam profanarum epistemon (Encyclopaedia, or Knowledge of the World of Disciplines, Basel, 1559) that the term became first recognized as a noun.
There have been two examples of the oldest
vernacular use of the compounded word. In approximately 1490, Franciscus Puccius wrote a letter to Politianus thanking him for his Miscellanea, calling it an encyclopedia. More commonly,
François Rabelais is cited for his use of the term in
The suffix -p(a)edia
Several encyclopedias have names that include the suffix -p(a)edia, to mark the text as belonging to the genre of encyclopedias. For example
Banglapedia (on matters relevant for Bangladesh).
Today in English, the word is most commonly spelled encyclopedia, though encyclopaedia (
from encyclopædia) is also used in Britain.