A WikiWiki (usually known as a wiki) is a web application which enables communities to collaboratively add, modify, or delete the content of a web site. Text is written using a simple markup language (called WikiMarkup) or a rich-text editor.

A single page in a wiki website is referred to as a "wiki page", while the entire collection of pages, which are usually well interconnected by hyperlinks, is "the wiki". A wiki is essentially a database for creating, browsing, and searching through information. A wiki allows non-linear, evolving, complex and networked text, argument and interaction.

Ward Cunningham, the developer of the first wiki software, WikiWikiWebContent unavailable! (broken link)https://jspwiki-vm1.apache.org/images/out.png, originally described it as "the simplest online database that could possibly work". "Wiki" comes from the Hawaiian word "wikiwiki" meaning "fast" or "quick". Ward Cunningham and co-author Bo Leuf, in their book The Wiki Way: Quick Collaboration on the Web, described the essence of the Wiki concept as follows:

• A wiki invites all users to edit any page or to create new pages within the wiki Web site, using only a plain-vanilla Web browser without any extra add-ons.
• Wiki promotes meaningful topic associations between different pages by making page link creation almost intuitively easy and showing whether an intended target page exists or not.
• A wiki is not a carefully crafted site for casual visitors. Instead, it seeks to involve the visitor in an ongoing process of creation and collaboration that constantly changes the Web site landscape.

See: the original WikiWikiWebContent unavailable! (broken link)https://jspwiki-vm1.apache.org/images/out.png or WikiContent unavailable! (broken link)https://jspwiki-vm1.apache.org/images/out.png on Wikipedia