The Name Servers of a domain show the DNS servers that manage its DNS records. The Internet protocol address of the site (A record), the mail server that takes care of the emails for a domain address (MX records), any text record in free form (TXT record), pointing (CNAME record) etc are extracted from the DNS servers of the hosting provider and for any domain name to be using them and to be pointed to their hosting platform, it should have their name servers, or NS records. If you would like to open a website, for instance, and you enter the URL, the Internet browser connects to a DNS server, which keeps the NS records for the domain address and the request is then sent to the DNS servers of the hosting company where the A record of the web site is obtained, enabling you to look at the content from the right location. Normally a domain address has a couple of name servers that start with NS or DNS as a prefix and the difference between the two is only visual.