Differences between Wikipedia, Wikimedia, MediaWiki, and wiki

Confused about the differences between MediaWiki, Wikimedia, Wikipedia and wiki?

== Wiki == Wiki is a generic term which is used to describe a certain kind of collaborative website that can be edited by any user and/or visitor; it is not a proper noun. See also: Wikipedia's entry on "wiki software".
 * wiki (as an adjective), the Wiki Way, and the antonym un-wiki are also used to describe the community-oriented philosophy that goes with such a system (e.g. "that's not a very wiki way of doing things").
 * Wiki (with a capital 'W') is an incorrect term, although it has sometimes been used to refer to either Wikipedia or the Portland Pattern Repository (also known as WikiWikiWeb), which was the first wiki to be created.
 * wiki software and wiki engine are terms referring to pieces of software that power wiki-based websites. There are many different types of wiki software; some very simple, others with advanced features.

For a more complete description, see Wikipedia's entry on "wiki".

== Wikimedia == Wikimedia is the collective name for a group of inter-related projects, including Wikipedia, Wiktionary, Wikisource, Wikibooks, and others, which aim to use the collaborative power of the Internet, and the wiki concept, to create and share free knowledge of all kinds. See also: Wikimedia movement, the Wikipedia article on the Wikimedia Foundation. The Wikimedia servers are not available for hosting projects not run by the Wikimedia Foundation. See also: Wikimedia servers.
 * Wikimedia Deutschland, Wikimedia Russia etc. are the names of various local chapters of enthusiasts of Wikimedia projects. They not part of they Wikimedia Foundation, though they usually have close contacts to it. The sites, the Wikimedia Foundation and the local chapters are sometimes all collectively referred to as the Wikimedia movement.
 * The term Wikimedia servers is often used, referring to the computer hardware on which all Wikimedia projects are hosted. The servers are run by employees of the Wikimedia Foundation, many of whom also work on the MediaWiki software (see below).
 * The Wikimedia Meta-Wiki, commonly referred to as Meta, is the wiki used to discuss issues which affect all Wikimedia projects. See also: About.
 * Meta should not be confused with MetaWiki, a search engine that is not part of the Wikimedia group of projects.

== Wikipedia == Wikipedia is a Wikimedia project that is a global, free and multilingual internet encyclopedia. It is the oldest, and largest, Wikimedia project, predating the Wikimedia Foundation itself. Wikipedia is a wiki that runs on MediaWiki.

== MediaWiki == MediaWiki is a particular wiki engine, that is developed for and used by Wikipedia and the other Wikimedia projects. MediaWiki is freely available for others to use (and improve), and it is in use by all sorts of projects around the world.

See also How does MediaWiki work?, Sites using MediaWiki, How to become a MediaWiki hacker.

== Video == on YouTube
 * [//www.youtube.com/watch?v=gXD1TRGafQ0 The State of Wikipedia]