The first or only domain name (with its extension) in a URL string. When one website hosts another website, the first domain name (with its extension) is the site name and the last domain name (with its extension) is the host name. For example, in the URL string “www.SecureWeb.com/aaa/www.example.com/home.htm,” the site name is “www.SecureWeb.com” and the host name is “www.example.com.”