Third level domain: using sitename.uwyo.edu as an example, the ".edu" portion of the name is considered the first level domain name, the ".uwyo" portion of the name is considered the second level domain name, and the "sitename" portion of the name is the third level domain name.
Domain name outside of the UW domain name scheme: using www.sitename.net as an example, because it does not include either the UW first or second level domain names (i.e. does not include "uwyo.edu"), it is entirely outside of the UW domain name scheme.
Note: As of February 11, 2009 all new DNS hosted sites will be created as basic UW web sites. The FrontPage Extended site option will no longer be available for DNS hosted sites and will no longer be an option for DNS hosted sites requested through the Central Site Requests pages.