Differences between Wikipedia, Wikimedia, MediaWiki, and wiki/id

Bingung tentang perbedaan antara MediaWiki, Wikimedia, Wikipedia, dan 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.
 * 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. See also: Wikipedia's entry on "wiki software".

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

Wikimedia
Wikimedia adalah nama kolektif untuk sekelompok proyek yang saling terkait, termasuk Wikipedia, Wiktionary, Wikisource, Wikibooks, dan lainnya, yang ditujukan untuk menggunakan daya kolaboratif Internet, dan konsep wiki untuk membuat dan berbagi segala jenis pengetahuan bebas.

Wikimedia is also the short name for the Wikimedia Foundation, a non-profit organization headquartered in San Francisco that runs these projects.
 * The term Wikimedia servers is often used, referring to the computer hardware on which all Wikimedia projects are hosted.
 * Wikimedia Deutschland, Wikimedia Russia etc. are the names of dozens local chapters of enthusiasts of Wikimedia projects. They are independent from the Wikimedia Foundation and the Wikimedia projects. Wikimedia, depending on the context and locale, is often incorrectly used as short name for the Wikimedia projects, or a chapter, or the Wikimedia Foundation (the latter can happen also on this wiki).
 * Wikimedia Meta-Wiki, biasa disebut Meta, adalah wiki yang digunakan untuk mendiskusikan masalah yang memengaruhi semua proyek Wikimedia. Lihat pula: About.
 * Jangan keliru antara Meta dengan MetaWiki, suatu mesin pencari yang tidak menjadi bagian kelompok proyek Wikimedia.

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.

Lihat pula How does MediaWiki work?, Sites using MediaWiki, How to become a MediaWiki hacker/id.

Video

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