DisAmbiguation is a term used in the WikiPedia for creating a page which acts to redirect ambiguous names to more specific ones.
It's one of those concepts that is best described with an example.
Imagine a page called "WikiZen" - people might go there looking to learn about the ZenOfWiki? or about WikiCitizens. As such, rather than place both meanings on the one page, the page WikiZen could act as a disambiguation page which redirects the WikiCitizen to whichever page they were looking for.