Wiktionary
n. A hyperlink that leads to multiple endpoints.
Wikipedia
A fat link (also known as a "one-to-many" link, an "extended link") or a "multi-tailed link" is a hyperlink which leads to multiple endpoints; the link is a multivalued function.
The hyperlinks that are attached to the same design object can be grouped into a fat link for representational purposes, and the activation of a fat link gives a menu of the links contained in it (cf. hyperlink history list), from which individual links can then be activated.
The concept is also covered in Grønbæk and Trigg's extended Dexter model, which cites the Instructional Design Environment.
The concept pre-dates the World Wide Web. However, there have been calls for fat links to be implemented on the web (e.g. Jakob Nielsen in his Alertbox for January 3, 2005 ).
The idea was implemented in 2007 by two services: first AFewURLs, then FatURL.
In 2011, Brief.ly launched a service allowing to have multiple links in tabs. It followed by Links2.Me and Many.at as well as Feed2Tabs and Links2Tabs plugins for WordPress. In 2012, Briefly.PRO version of the platform allowed anyone to run similar services on their own domain names.
Usage examples of "fat link".
When they were finished and the Engineer was once more upright on his feet, holding himself in position like the rest with a hand on one of the hull or ceiling anchor points, he looked like a figure made out of very short lengths of fat link sausage, each tie compartmentalizing a section of his arm or leg.