Wikipedia (/ˌwɪkɪˈpdiə/ (listen) wik-ih-PEE-dee-ə or /ˌwɪki-/ (listen) wik-ee-) is a multilingual free online encyclopedia written and maintained by a community of volunteers through open collaboration and a wiki-based editing system. Individual contributors, also called editors, are known as Wikipedians. Wikipedia is the largest and most-read reference work in history.[3] It is consistently one of the 15 most popular websites ranked by Alexa; as of 2022, Wikipedia was ranked the 10th most popular site.[3][4] It is hosted by the Wikimedia Foundation, an American non-profit organization funded mainly through donations.[5]

On January 15, 2001, Jimmy Wales[6] and Larry Sanger launched Wikipedia; Sanger coined its name as a portmanteau of "wiki" and "encyclopedia."[7][8] Wales was influenced by the "spontaneous order" ideas associated with Friedrich Hayek and the Austrian School of economics, after being exposed to these ideas by Austrian economist and Mises Institute Senior Fellow Mark Thornton.[9] Initially available only in English, versions in other languages were quickly developed. Its combined editions comprise more than 58 million articles, attracting around 2 billion unique device visits per month and more than 17 million edits per month (1.9 edits per second) as of November 2020.[10][11] In 2006, Time magazine stated that the policy of allowing anyone to edit had made Wikipedia the "biggest (and perhaps best) encyclopedia in the world."[6]