The Name Servers of a domain reveal 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 emails for a domain name (MX records), any text record in free form (TXT record), pointing (CNAME record) and so forth are taken from the DNS servers of the website hosting provider and for any Internet domain to be using them and to be forwarded to their hosting platform, it ought to have their name servers, or NS records. If you wish 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 site is obtained, allowing you to see the content from the right location. Normally a domain has two name servers that start with NS or DNS as a prefix and the distinction between the two is just visual.