WikiServer is the generic term for a server that specializes in, or is dedicated to, serving the pages of a wiki, such as this c2 wiki created by WardCunningham.
As another example, a WikiServer called "WikiServer" was produced in CeePlusPlus by EddieEdwards, implementing the bare bones of HTTP/1.0 and providing a wiki for use under MicrosoftWindows. It is reasonably popular for note sharing and simple wiki use on an intranet or the Internet. For further information on all versions, see EddiesWiki. The latest version of the WikiServer (WxWikiServer) is maintained by Ryan Norton, and can be found on http://www.wikiserver.org.
Just trying to understand: InstikiWiki comes with its own webserver, but that is built over the WEBrick library (a ruby library to build webserver-like applications). Is it considered a WikiServer? Yes, I would think so.
See WikiEngines.