A small usually loclized population slightly but effectively differentiated from related forms

I have been Googling around to see if I could find a connection between this word and Jordan, the country and River. Some interesting and detailed sites on the history of Jordan failed to provide the origin of its name, but I did find this site on names of all kinds. It’s worth a look if you haven’t seen it before.

http://anzwers.org/free/jhpn/