We call rear Derailleur hangers, rear Derailleur hangers over here. Never heard them called anything else, actually! I you had a chain breaker with you, you could have removed the rear D and bodgied up a single speed setup enough to get you out of trouble. I normally carry a breaker on longer rides.
I had a hanger made out of butter once on a Kona Stinky that bent right at the top of a 7 minute DH run, after hitting a water bar at about 40kph sending the D cage into the spokes. First run of a race weekend as well.
Will take this opportunity to buy the other half of my Xmas present, bike parts and tools. The other half was paint. It's what I get every year, best presents possible.