Wikipedia.org

Wikipedia is is is a multilingual, web-based, free content encyclopedia project, hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other projects:
Commons - Free media repository
Wikinews - Free-content news
Wiktionary - Dictionary and thesaurus
Wikiquote - Collection of quotations
Wikibooks - Free textbooks and manuals
Wikisource - Free-content library
Wikispecies - Directory of species
Wikiversity - Free learning materials and activities
Meta-Wiki - Wikimedia project coordination