One of the most fundamental part of DNS (Domain Name System). Nameserver is specialised to handle queries about the location of the domain name’s services. In other words, nameservers interpret your domain’s current DNS provider.
You will be using these nameservers for an external domain name if you are hosting them with Vodien. Learn more on how to host an external domain name.
Any troubles with the difference between Parked Domains vs Addon Domains, click the linked guide for more information.