NickName

I renamed the NickName to User Name in the admin page (join/edit/view profile). Why the member login page still shows NickName?

You have to edit all nickname blocks, since there are several lang keys, _nickname( in join page, edit, view...)

NickName is a system name - I wouldn't change it unless you really know what you are doing.  Instead change the "caption" field in that block.

I changed the caption to 'Use Name'. However, the member login page still shows 'NickName'. Any idea? Thanks,

maybe if you go to admin---> settings---->languages----> and search for NickName....then change all results to User Name...

or download langs/lang_en.php and edit it...

Excellent!