When linking to a page on a well known wiki, you might want to use an URL abbreviation such as Oddmuse:URL Abbreviation. In this case, “Oddmuse” is the abbreviation for the longer Oddmuse URL. These abbreviations are registered on the InterMap.
This interlink prefix is therefore variously called abbreviation, qualifier, or interlink moniker.
For more thoughts about “seamless integration” across multiple wikis, see InterWiki.