Middle school students at College des Colombieres in Versoix, Switzerland, above, are contributing to the world's largest encyclopedia and one of the most-visited websites—Wikipedia.

Photograph courtesy Gabriel Thullen
  • On Sept. 9, 2007, the English version of Wikipedia catalogued more than 2 million articles, making it the largest encyclopedia in history. The Wikipedia Foundation is based in San Francisco, California.

    Wikipedia is online-only and free to use. Anyone can use information found in its entries, if they follow certain rules. “Imagine a world in which every single person on the planet is given free access to the sum of all human knowledge. That's what we're doing,” says founder Jimmy Wales.

    Wikipedia is managed by a dedicated group of editors, who write, edit and update its encyclopedic entries. The project has also evolved into a fairly reliable source of information—a 2005 study by the journal Nature compared it favorably to Encyclopaedia Britannica.

  • Term Part of Speech Definition Encyclopedic Entry
    catalog Verb

    to list or order by type.

    editor Noun

    person who regulates and manages the language and concepts of a publication.

    encyclopedia Noun

    book, set of books, or set of articles offering introductory or comprehensive information on a branch of knowledge or a particular subject.

    journal Noun

    record of events, updated regularly.

    reliable Adjective

    dependable or consistent.

    Wikipedia Noun

    free, multi-lingual Internet encyclopedia written and edited entirely by volunteers.