The Name Servers of a domain point out the DNS servers that handle its DNS records. The IP address of the site (A record), the mail server that manages the e-mails for a domain address (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 domain address to be using them and to be pointed to their hosting platform, it has to have their name servers, or NS records. If you would like to open an Internet site, for example, and you input the URL, the web browser connects to a DNS server, which keeps the NS records for the domain and the request is then sent to the DNS servers of the hosting provider where the A record of the website is obtained, so you can see the content from the right location. Commonly a domain address has 2 name servers that start with NS or DNS as a prefix and the distinction between the two is simply visual.
