As you would hopefully be aware, a Domain Name is the character-based address which is entered into a browser to take you to a website. It's also the part after the @ symbol in an email address.

These can be registered via a Registrar, and the person or group that registers the Domain Name then is referred to as the Registrant. The Registrar holds the Domain Name records which include the location of the Name Servers.

DNS is the name given to a hierarchy of servers which hold the list of locations that correspond to Domain Names and their services. Essentially, it's a phone book. The Domain Name equates to the name, and the location (IP Address) equates to the phone number. Name Servers store the information for Domain Names as records in something called a Zone. Information such as the location of the website server & email server and the like.

(The IP Address simply the term used for the unique address that identifies a computer or device on a network - even if that network is massive, like the Internet. Think of it as a server or computers phone number.)

These names are given to the system that is holding/providing the records for a domain name.

These take on slightly different context depending on your position.

When the context is hosting (website, email, etc) then these mean the definative location of your DNS Zone. It's authoritative as it is the primary place holding information about a domain.

However, if the context is a computer users access to the internet (or network), then a DNS Server is the server that obtains DNS records for your computer from the authoritative name server for a particular domain name.

To explain this, I'll use a slightly simplified example: When you loaded this website, your computer would have needed to look up the domain tfcs.com.au.

1. Your computer would have requested the DNS record for tfcs.com.au from your networks DNS Server.
2. That DNS Server would have checked it's "recent call list" (cache) to see if it had the domain details already. If not, it would seek out the Name Server holding the authoritative records, and pass them on to your computer.
3. Once your computer has the IP Address of our website server, it then talks direct to that server to display the website.

The same process applies to email, or any other Internet based service. To facilitate that, there are different record types so that the relevant information can be retrieved from the DNS servers.