Wikipedia (IPA: /ˌwikiˈpiːdi.ə/, /ˌwɪkiˈpiːdi.ə/, or /ˌwaɪkiˈpiːdi.ə/ (Audio (U.S.) (help·info)) is a multilingual, web-based, free content encyclopedia project. Wikipedia is written collaboratively by volunteers; the vast majority of its articles can be edited by anyone with access to the Internet. Wikipedia's name is a portmanteau of the words wiki (a type of collaborative website) and encyclopedia. Its primary servers are in Tampa, Florida, with additional servers in Amsterdam and Seoul.
Wikipedia's English edition was launched on January 15, 2001, as a complement to Nupedia, an expert-written and now defunct encyclopedia. The project is currently operated by the Wikimedia Foundation, a non-profit organization created by Jimmy Wales, the co-founder of Wikipedia. Wikipedia has approximately 7.2 million articles in 251 languages, 1.7 million of which are in the English edition. It has steadily risen in popularity since its inception, and currently ranks among the top fifteen most-visited websites worldwide.
Due to its open nature, critics have questioned Wikipedia's reliability and accuracy. The site has also been criticized for its susceptibility to vandalism, uneven quality, systemic bias and inconsistencies, and for favoring consensus over credentials in its editorial process. Wikipedia's content policies and sub-projects set up by contributors seek to address these concerns. Two scholarly studies have concluded that vandalism is generally short-lived and that Wikipedia is generally as accurate as other encyclopedias.