A wiki (sometimes spelled "Wiki") is a server program that allows users to collaborate in forming the content of a Web site. With a wiki, any user can edit the site content, including other users' contributions, using a regular Web browser. Basically, a wiki Web site operates on a principle of collaborative trust. The term comes from the word "wikiwiki," which means "fast" in the Hawaiian language.
A wiki allows a visitor to the "wikified" Web site to edit the content of the site from their own computer. Visitors can also create new content and change the organization of existing content. The simplest wiki programs allow editing of text and hyperlinks only. More advanced wikis make it possible to add or change images, tables, and certain interactive components such as games.
A wiki provides a simplified interface. At any time, contributors can conveniently view the Web page as it looks to other subscribers, before and after the changes they have made. It is not necessary to know HTML (hypertext markup language) or perform work in HTML code. The best known example of a wiki Web site is Wikipedia, an online dictionary building collaboration.