category - a collection of pages linked by topic. Category tags are in the form Category:Computers and are listed at the bottom of a page. The part after the ":" is the name of the category. A list of basic categories to browse through can be found at Category:Fundamental categories.
Community portal - one of Wikipedia's main project pages. It can often be found on the sidebar (on the left side in most skins), and is a page that lists the collaboration of the week, outstanding tasks that need to be addressed, and several other useful bits of information and resources. The Community Portal is useful for picking an article or topic to work on or read.
coordinates - articles about specific places may have coordinates. Clicking on these leads to a list of maps for the location.
disambiguation - the process of resolving the conflict that occurs when articles about two or more different topics have the same natural title.
disambiguation page - a page that contains various meanings of a word, and refers to the pages where the various meanings are defined. In cases when there is a prevailing meaning of the term, disambiguation pages are named "subject (disambiguation)".
discussion - a link at the top of a page that leads to the discussion for that page (also called its talk page).
Featured article, an article that has been selected as representing "the best of Wikipedia".
free link - a link pointing to another page within Wikipedia or its sister projects, sometimes referred to as wikilinks or internal links. Unless otherwise specified in a user's monobook.css, these links usually show up as blue if they are working and you haven't visited them before, red if they are broken or don't yet exist, and purple if they are working and you have visited them before.
interwiki - a link to a sister project; this can be an interlanguage link to a corresponding article in a different language in Wikipedia, or a link to another project.
IP (Internet Protocol) - a protocol used for communicating data across the Internet. The numerical IP address is used for tracking the edits of anonymous contributors (editors who are not logged on as a user).
IPA (International Phonetic Alphabet) - widely used on Wikipedia to indicate pronunciation. See also Help:IPA, Help:IPA for English, the more detailed IPA chart for English dialects, and Wikipedia:Manual of Style (pronunciation).
ISBN (International Standard Book Number) - these are usually shown as a wikilink. Clicking the link allows for searching a range of library cataogues for that particular book.
Main Page - the page to which every user not specifying an article is redirected. The Main Page contains links to current events, presents certain articles (like a featured article of the day and links to Wikipedia's newest articles), and serves as an entry point to browsing all articles by topic or other classification. Links to sister projects and other-language Wikipedias are also a prominent feature on the Main Page. Due to its high exposure, all content on the Main Page is protected.
MediaWiki - the software behind Wikipedia and its sister projects, as well as several projects not related to Wikimedia.
namespace - a way to classify pages. Wikipedia has namespaces for encyclopedia articles, pages about Wikipedia (project namespace), user pages (User:), special pages (Special:), template pages (Template:), and talk pages (Talk:, Wikipedia talk:, and User talk:), among others. See also Wikipedia:Namespace.
page - any individual topic within Wikipedia; the web page without the top, bottom and sidebars. Pages include articles, stubs, redirects, disambiguation pages, user pages, talk pages, documentation and special pages.
Portal - pages intended to serve as "Main Pages" for specific topics or areas.
protected page - indicates a page that cannot be edited except by administrators, or in some cases, established users. Usually this is done to cool down an edit war. See also Wikipedia:This page is protected.
Random page - on the left of each page for most skins. It will take you to a Wikipedia article that is chosen by a computer algorithm without any deliberate pattern or meaning to the choice.
Recent changes - a real-time list of changes Wikipedia editors have made to articles
Redirect, redir - a page title which, when requested, merely sends the reader to another page. This is used for synonyms and ease of linking. The name of the redirected page is shown under the title of the resulting target page. For example, impressionist might redirect to impressionism. See also Wikipedia:Redirect.
Red link, redlink - a wikilink to an article that does not exist shows up red. See also blue link.
sister project- one of a number of wikis related to Wikipedia. They are listed on the Main Page
skins - the appearance theme in Special:Preferences. The default skin is called Vector, and eight others are available to logged-in users: Chick, Classic, Cologne Blue, Modern, Monobook, MySkin, Nostalgia, and Simple.
stub - an article considered too short to give an adequate introduction to a subject (often one paragraph or less). Stubs are marked with stub templates, a specific type of cleanup template, which add the articles to stub categories sorted by subject matter.
wiki - any website that allows the easy creation and editing of any number of interlinked web pages via a web browser using a simplified markup language. Wikipedia is the most well known example of a wiki.
Wikibook - a Wikipedia sister project that works to develop free textbooks, manuals, and other texts online.
wikilink - an internal link to another page within Wikipedia.