Wikipedia is a free, open content online encyclopedia created through the collaborative effort of a community of users known as Wikipedians. Anyone registered on the site can create an article for publication; registration is not required to edit articles.

Wikipedia was launched on January 15, 2001 as a single English-language edition at www.wikipedia.com, and was announced by Sanger on the Nupedia mailing list. The name originated from a blend of the words wiki and encyclopedia. Its integral policy of "neutral point-of-view" was codified in its first few months.

Wikipedia is free content that anyone can edit, use, modify, and distribute. This is a motto applied to all Wikimedia foundation project: use them for any purpose as you wish.

The name was suggested by Sanger on 11 January 2001 as a portmanteau of the words wiki (Hawaiian for "quick") and encyclopedia. The wikipedia.com and wikipedia.org domain names were registered on 12 and 13 January, respectively, with wikipedia.org being brought online on the same day.