Wikipedia
Wikipedia (i or i WIK-i-PEE-dee-ə) is a free-access, free-content Internet encyclopedia, supported and hosted by the non-profit Wikimedia Foundation. Those who can access the site can edit most of its articles. Wikipedia is ranked among the ten most popular websites, and constitutes the Internet's largest and most popular general reference work.
Jimmy Wales and Larry Sanger launched Wikipedia on January 15, 2001. Sanger coined its name, a portmanteau of wiki and encyclopedia. Initially only in English, Wikipedia quickly became multilingual as it developed similar versions in other languages, which differ in content and in editing practices. The English Wikipedia is now one of 291 Wikipedia editions and is the largest with 5,081,662 articles (having reached 5,000,000 articles in November 2015). There is a grand total, including all Wikipedias, of over 38 million articles in over 250 different languages. As of February 2014, it had 18 billion page views and nearly 500 million unique visitors each month.