Wikipedia.org defines wiki as :
A Wiki or wiki (pronounced “wicky” or “weekee”) is a website (or other hypertext document collection) that allows any user to add content, as on an Internet forum, but also allows that content to be edited by any other user.The term can also refer to the collaborative software used to create such a website (see Wiki software).
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wiki comes from the Hawaiian term for “quick” or “super-fast”.