The Name Servers of a domain show the DNS servers that are responsible for its DNS records. The IP address of the web site (A record), the mail server that handles the e-mails for a domain address (MX records), any text record in free form (TXT record), pointing (CNAME record) and so on are extracted from the DNS servers of the hosting provider and for any Internet domain to be using them and to be forwarded to their hosting platform, it has to have their name servers, or NS records. If you wish to open a website, for example, and you input the URL, the browser connects to a DNS server, which keeps the NS records for the domain name and the request is then pointed to the DNS servers of the hosting provider where the A record of the web site is retrieved, allowing you to see the content from the right location. Usually a domain name has a couple of name servers that start with NS or DNS as a prefix and the distinction between the two is only visual.