So it is “Long short-term memory”. And why not only long memory or short-memory? Why do we use them both?
Well, maybe it can do both long and short depending on the situation? Maybe they could have called it “medium”. Or who knows, maybe the person who created this idea had a sense of humor? When you write the paper about your next great discovery, you get to choose what you want to call it.
You might also check out the LSTM’s paper for any insight behind its name.