What is a DNS server?

Everything on the Internet (or on any other TCPI/IP network) is referenced by an IP address, which is a 32-bit number that is usually represented as four 8-bit numbers joined by periods. These IP numbers are not convenient for humans to remember, and sometimes they change.

For us humans, it is much more convenient to refer to things on the net by using domain names instead of raw IP addresses. For example, it is easier to remember WWW.ANSWERBAG.COM than it is to remember [66.35.213.113].

DNS stands for — depending on context — “Domain Name Server” or “Domain Name Service”, and refers to the process by which a human-friendly domain name is converted into the numeric IP address that is needed to access the desired resource.

At the bottom level, the Internet knows machines by numbers. Each machine on the net has a numberm its IP address, which is of the form 10.153.200.17. Some of them are permanent, some temporary. But whichever way they are assigned, they are to say the least not human friendly. So they invented the domain naming system with names like mymachine.mydomain.mycompany.co.uk. The Domain Naming System (DNs) is the system that converts the long, human friendly, name into the numbers that the computers work on. YOu put in a domain name and get out an IP address.

It works by dismantling the sections of the name in reverse order. .uk is a Top Level Domain or TLD. To find that, you would have to go to one of the 14 top level servers scattered on secures sites around the world. YOu would ask it where the server for .uk is. Then you go to the .uk server and ask it for the server for .co.uk, then go to that server and ask for mycompany.co.uk and so on. In practice, you never do that, because all the intermediate servers remember (or cache) the answer to recent lookups. So they will remember names, or pars of names, that anybody else has used in the last 24 hours.

Short for Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned.
Short for digital nervous system, a term coined by Bill Gates to describe a network of personal computers that make it easier to obtain and understand information.

he purpose of a DNS server is to enable people and applications to lookup records in DNS tables. Most DNS servers are now private, meaning that they are configured to only provide service to the people and organizations who own and maintain them.

A few domain name servers on the Internet provide DNS resolutions for anyone who requests it of them. These are known as "Public DNS Servers."

A DNS server is any computer registered to join the Domain Name System. A DNS server runs special-purpose networking software, features a public IP address,and contains a database of network names and addresses for other Internet hosts.

DNS Root Servers
DNS servers communicate with each other using private network protocols. All DNS servers are organized in a hierarchy. At the top level of the hierarchy, so-called root servers store the complete database of Internet domain names and their corresponding IP addresses. The Internet employs 13 root servers that have become somewhat famous for their special role.

It's a domain name server. In short, it directs your domain name (example.com) to your site's IP address (000.000.0.00). More information can be found here: http://en.wikipedia.org/wiki/Name_server