The Name Servers of a domain name point out the DNS servers that manage its DNS records. The IP of the web site (A record), the mail server that deals with the emails for a domain name (MX records), any text record in free form (TXT record), forwarding (CNAME record) and so on are obtained from the DNS servers of the website hosting company and for any Internet domain to be using them and to be pointed to their hosting platform, it should have their name servers, or NS records. If you want to open an Internet site, for instance, and you type in the URL, the browser connects to a DNS server, which keeps the NS records for the domain address and the request is then forwarded to the DNS servers of the hosting provider where the A record of the website is retrieved, allowing you to see the content from the correct location. Ordinarily a domain has 2 name servers that start with NS or DNS as a prefix and the distinction between the two is just visual.