Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 16 million articles (over 3.4 million in English) have been written collaboratively by volunteers around the world, and almost all of its articles can be edited by anyone with access to the site. Wikipedia was launched in 2001 and is currently the largest and most popular general reference work on the Internet. The name Wikipedia is a portmanteau from wiki (a technology for creating collaborative websites, from the Hawaiian word wiki, meaning 'quick') and encyclopedia. Registration not required.