The Name Servers of a domain show the DNS servers that are responsible for its DNS records. The Internet protocol address of the web site (A record), the mail server that takes care of the emails for a domain name (MX records), any text record in free form (TXT record), directing (CNAME record) etc are obtained from the DNS servers of the web hosting company and for any domain address to be using them and to be forwarded to their hosting platform, it needs to have their name servers, or NS records. If you wish to open a website, for instance, and you type in the URL, the browser connects to a DNS server, which keeps the NS records for the domain and the request is then redirected to the DNS servers of the hosting company where the A record of the site is obtained, allowing you to see the content from the correct location. Normally a domain name has 2 name servers that start with NS or DNS as a prefix and the distinction between the two is only visual.