Shell Corporation
  
Most companies do something. Apple makes iPhones. Amazon sells stuff. Crazy Jim's TV Emporium Inc. sells TVs. And mattresses, for some reason.
Shell corporations are different. They don't do...anything. They don't have workers. They don't have factories. They don't buy or sell anything. They exist as legal entities...a name on a document filed with regulators.
Now, just because they don't do anything doesn't mean they don't serve a purpose. Your garden gnome doesn't do anything either, but he serves an important purpose. (He makes your garden look fantastic.)
Often shell corporations hold an interest in assets, or other companies. They can be used to disguise ownership or to create a legal buffer in certain situations. As such, you often hear about them as part of some investigation...like, "It turns out that El Chapo owned a chain of day-care centers, through a series of shell corporations."