This question was asked over on Slate’s The Fray. What is a “...-pedia”. I found one place that said it was Greek for the upbringing of a child. Is that correct? So how, when, where did this suffix get tacked onto encyclopedia and wikipedia?

Paideia is Greek for ‘education’ (it’s from pais, genitive paidos, ‘child’).  The ancient Greeks had a phrase enkyklios paideia ‘encyclical education,’ meaning (in the OED’s words) ‘the circle of arts and sciences considered by the Greeks as essential to a liberal education’; at some point this got misread as a single word, enkyklopaideia, which in Latinized form became encyclopaedia.  The word, borrowed into English, at first meant “The circle of learning; a general course of instruction,” then “A literary work containing extensive information on all branches of knowledge, usually arranged in alphabetical order.” The OED adds: “The word in this sense appears first as the title of certain works published in the 17th cent. esp. that of Alstedius.” Wikipedia (and other -pedia words) are modeled after encyclopedia, just as -mat words (laundromat, etc.) are modeled after automat.

It’s interesting that works differed in the form they chose, for instance, Encyclopaedia Britannica, but Pears Cyclopeadia (the latter often forming part of the Christmas bounty when I was a kid.) I always used to wonder if there was any rhyme or reason to the variation, but I’m sure there wasn’t.

The OED says “A shortening or modification of ENCYCLOPÆDIA (itself due to an erroneous Greek reading), perh. intended to convey more obviously the ostensible sense ‘circle of learning’.” First cite for the ‘circle of learning’ sense:

1636 SIR H. BLOUNT Voy. Levant 85 This Cyclopædia hath beene observed to runne from East to West: Thus have most Civilities, and Sciences come..from the Indian Gymnosophists into Egypt, from thence into Greece, so into Italy.

And for the ‘book’ sense:

1728 CHAMBERS (title), Cyclopædia, or General Dictionary of Arts and Sciences.

(Aldi, you’ve got to start making more comments, so you can break the 31-comment barrier and get your second box!)

Ha! Just noticed. Prepare for a slew of inconsequential comments. Such as this one. :)

So where does the Wiki- part of Wikipedia come from?

From Wikipedia’s entry on “Wiki”:

A wiki (IPA: [ˈwɪ.kiː] <WICK-ee> or [ˈwiː.kiː] <WEE-kee>[1]) is a website that allows the visitors themselves to easily add, remove, and otherwise edit and change available content, typically without the need for registration. ... WikiWikiWeb was the first of such software to be called a wiki. Ward Cunningham started developing WikiWikiWeb in 1994 and installed it on Internet domain c2.com on March 25, 1995. It was named by Cunningham, who remembered a Honolulu International Airport counter employee telling him to take the so-called “Wiki Wiki” Chance RT-52 shuttle bus line that runs between the airport’s terminals. According to Cunningham, “I chose wiki-wiki as an alliterative substitute for ‘quick’ and thereby avoided naming this stuff quick-web.” “Wiki Wiki” is a reduplication of “wiki”, a Hawaiian-language word for fast. The word wiki is a shorter form of wiki wiki (IPA /wiːkiː wiːkiː/).