Wiki software subclass of web application
Wiki software (also known as a wiki engine or a wiki application), is collaborative software that runs a wiki, which allows the users to create and collaboratively edit pages or entries via a web browser. A wiki system is usually a web application that runs on one or more web servers. The content, including previous revisions, is usually stored in either a file system or a database. Wikis are a type of web content management system, and the most commonly supported off-the-shelf software that web hosting facilities offer.
There are dozens of actively maintained wiki engines. They vary in the platforms they run on,  the programming language they were developed in, whether they are open-source or proprietary, their support for natural language characters and conventions, and their assumptions about technical versus social control of editing.
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