The NS, or Name Server records of a domain, point out which servers manage the Domain Name System (DNS) records for it. Setting the name servers of a given host company for your domain address is the most effective way to direct it to their system and all its sub-records are going to be handled on their end. This includes A (the IP address of the server/website), MX (mail server), TXT (free text), SRV (services), CNAME (forwarding), and so forth, so, in case you need to change some of these records, you are going to be able to do it using their system. To put it differently, the NS records of a domain name point out the DNS servers which are authoritative for it, so when you attempt to open a web address, the DNS servers are contacted to retrieve the DNS records of the domain name you are attempting to access. This way the web site you'll see is going to be retrieved from the correct location. The name servers normally have a prefix “ns” or “dns” and each domain has at least two NS records. There is absolutely no practical difference between the two prefixes, so what kind a website hosting provider is going to use depends solely on their preference.