Ringtails

Silly question, just in case someone may know... WHAT, exactly, is a "ringtail"? Way back in 2000 or so, I assumed they were lemurs (even if they didn't look that much like them), but after having seen "grey fox ringtails" or "Fennec ringtails" (which don't seem to look like ANY of the three, save having pointed noses and stripey tails) I'm completely bemused, now. *headscratch*