Emacs uses keybindings with "LFD", the Emacs FAQ provides the following information:
LFD: Linefeed or Newline; same as `C-j'
Is there a
Linefeed button on my keyboard (other than
Don't think so. In your keyboard, probably, you have only the "return", "enter" key. There's no linefeed in regular IBM-PC keyboard.
In windows you can use the Shift + Enter to mean a linefeed: http://msdn.microsoft.com/en-us/library/ms646268%28v=vs.85%29.aspx
Apparently some keyboards do have an LFD key, because the BASH docs also mention this: