Although Emacs commonly refers to an editor, It was always so very much more: It is a compiler, an editor, a pain-in-the-arse, one of the most brilliant uses of the blurring of the layers of App/os/hardware. Its a lisp editor, a lisp development environment, a lisp machine, an OS, Its a database, a word processor, a calculator... the only things in computer science that It is not is a spread sheet, and a paint program, but do not say that too loud or someone will write a macro for it that does both of these things, in some weird way, you will have visions of Phillip K. Dick.

Oh, and did I say it was also a threaded-mail reader? A threaded-news reader?

Oh, and lastly, Emacs is a torture device.