I'm sure many butchers are pretty angry with us now since we know about the hanger steak...
Previously known as the "Butcher Steak", since butchers would keep and enjoyed it for themselves when consumers didn't know to ask for it. Now called the hanger steak (hence the name) because it hangs between the rib and the loin, supporting the diaphragm.
The location of the cut makes it one of the most tender steaks, but if not cooked properly (cook hot and fast on the heat) it can become tough. Its a rare cut, so once mastered- you'll be sure to impress everyone with its flavor and background.