What is a Wiki?
It’s like a hotel visitor book. As opposed to a hotel brochure. The content is made up entirely of public contributions.
noun: wiki; a website that allows collaborative editing of its content and structure by its users.
It’s like the wiki wiki bus. Howard Cunningham, the developer of WikiWikiWeb in 1995, learned the word on a visit to Hawaii Airport, where he was told to take the wiki wiki bus between the airport terminals. It means ‘superfast’ –- appropriate as the open nature of Wiki sites means they can grow exponentially.
(from the Sideways Dictionary web site)