If you are new to IT, you probably heard about "domain name" and you might be questioning yourself "
What is a domain name ?". Well before we dive deeper into answering the question "what is a  domain name? " , let us first clear our self with some basics on "what  is a domain name? " then we could dive deeper into defining Domain  names, Their types, TLD's, How to register domain name and much more  beyond if you keep on reading.
Basics on What is a Domain name?A domain name in general is the name a website has. But in earlier days  of internet websites did not had names and where not always live. In  earlier days you need to remember a long digits of numbers to visit a  website. like 119.18.56.83 is the server IP address of a website. Just  think how hard it would be remember a website if you did not note down  it's IP address. This really made internet an ugly and tough thing for  visitors. I mean how could a visitor remember the big numerical digit if  he wants to visit Facebook or Google. For computers it is more than  fine to remember big numerical digits because they operate on binary  system but what about us "can we really type the big numerical digit on  our web browser each time we want to visit a website? ".
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How to create a website for free Simply no, this was the only reasons why the need of domain naming  system arrived and one can say that this Domain name invention proved  revolutionary to internet. Now people could visit Facebook  without necessarily remembering the numeric terms i.e. IP address.
Since we now have domain name system, it is helping both the visitor and  the machines at the same time. Now users don't have to type the big  numeric terms and computers can still very effectively relate the user  query and so them the relevant results by patching the domain names with  the server IP of the website. so it sounds more user as well as  computer friendly and this makes internet a better place to visit.
Although domain names are simply patched with numeric terms known as IP  address but that's not all a domain name consists of. An IP address is  there on a domain name to point out the server location of a website but  they usually do not make up all of it, like what we see in an IP  address.
What is Domain Name format ?
Above we have discussed some basics on what is domain name ?, it's need,  evolution etc. It's time to dive deeper into what is domain name?, how  is it named, It's format etc.
A domain name has 4 parts:
- URL of the domain name.
 - The "WWW" of the domain name
 - The body of the domain name
 - The extension of the domain name
 
The 1st part of the domain name:
URL is the very first part a domain has. URL is an acronym for  Uniform resource locator. The function of  URL in a domain name is to  instruct the web browser to point a domain name where.i.e. It's is  usually found "http://" in a domain name which instruct the web browser  to point a hypertext document usually "html" acronym for hyper text  document. If we want to understand in simple terms usually in layman's  language http:// in a URL would  mean to point a webpage. In other cases  it can be "https://" of even "ftp://". Ftp is acronym for file transfer  protocol. A "ftp://" in domain name would suggest the web browser to  transfer files. A webmaster would go for ftp in his domain name if he  want to permit it's visitors to download files stored on his server, on  his website.
The 2nd part of the domain name:
WWW is the Second part a domain has. WWW is acronym for world  wide web. The purpose of WWW in a domain name is to tell both the  visitors and bots that the domain is a web property. It is now  also considered as deprecated since most of the web users no longer  type WWW in a domain name. WWW is followed by the actual name of a  website.
The 3rd part of the domain name:
The body of the domain name is the third and the most important part of a domain name. The  body of domain name is the main remembereable part of a domain name.  Users are free to decide the name of the body part. The naming could be  done according to ones wish like it could be words or phrases or  a combination of letters, words and phrases. The word limit of the body  of the domain name is 63 letters but it is always advisable to keep it  short usually withing 16 words. There are certain things a webmaster  should consider while registering the domain name like shortness,easy to  remember and SEO friendly for search engines.
The 4th part of the domain name:
The 4th and the final portion part of a domain name is the domain name extension but what is domain name extension ?
.well, A domain name extension lets user as well as the web browser know  more about the origin of a website. i.e. If a domain name ends with an  extension ".com"  then this specifies both web browser and the user that  this website is a commercial website. Domain name ending with extension  ".edu" will mean a website is for educational purpose.
.com extension is most widely used and very popular also. So it is  also advisable to go for .com domain name if available. .com,.org and  .net extensions are most popular and also a TLD so one should register  his domain with these extensions if available. Suggesting that .com,.org  and .net are most popular and should be used while registering a domain  name does not mean that other extensions are bad or should not be used.  Think of wikipedia.org, Wikipedia ends with .org extension and is a  very popular site. It's not the extension or name but what matters most  is the content of a website.
If you want further info on what a domain name extension is?, then you  must know that other than TLD's a domain extension is also based on the  geographic location i.e. A country based extension  e.g. ".fr" domain  extension simply specifies that this website is from France  ".jp" for  japan. A ".in" would mean a website from India. These domain extensions  can also be state wide e.g ".ca" represents the California state of  America. These "domain extensions" if used wisely could prove excellent  for localized marketing.
What is Top level Domain Name ?
A top level domain name is generally denoted to .com,.net and .org  extension. A top level is also denoted as TLD. In the hierarchical  domain system a top level domain occupies root zone of DNS(Domain name  system).  So every top level domain fills the first level of DNS zone  also known as top zone or root zone.
In 1980's, When DNS was designed, the Domain Name Space was given two division:
- ccTLD
 - gTLD
 
What is ccTLD ?A
 ccTLD stands for Country code top level domains. A ccTLD mainly consists of 2 character territory codes.
What is gTLD?A gTLD stands for generic Top level domain. A generic top level domain  category was made to  represent a set of categories domains ranging from  different multi level organization. These multi level organization  ranges from government sector, Education sector, Commercial sector,  Military sector, Organization, Network and International sector.
- Top level domain for government sector - .gov
 - Top level domain for Education sector- .edu
 - Top level domain for Commercial sector- .com
 - Top level domain for Military sector- .mil
 - Top level domain for Organization- .org
 - Top level domain for Network - .net
 
As the internet grew overtime, It become demanding to create additional  generic top level domains. According to the sources in October 2009  there were 21 generic top level domains and around 250 two letter  country top domains on the internet but as ICANN started a new policy  towards naming domain names, It became possible to name new top level  domains with new extension.
What is Second level Domain name?A second level domain name is also called a lower level domain name. A  second level domain name denoted with SLD occupies the second position  in Domain Hierarchy system of DNS.
A second level domain comes just after Top level domain in the DNS. i.e.  A second level domain assigns the left position after top level  domains. e.g. Google.co.in here ".in" is the top level domain  representing India while ".co" in the left of ".in" in the domain name  Google.co.in represents a second level domain name.
What is Third level Domain name?A third level domain name is the domain name which is writeen left to  second level domain name. A third level domain name comes just after  second level domain name.
Like third level domain there can also be fourth level domain and fifth  level domain and so on. Each of these level domain name comes after one  other and each of them are written on the left side one after the other.  A typical example of a domain name with 4 level of doamin levels is  "www.sos.state.oh.us". Here www stands for world wide web. "SOS" in the  domain name is called the sub domain of "state.oh.us". "State" here also  known as the sub domain name of "oh.us", "oh" is the sub domain name of  "us" and last but not least "Us" here also means a top level domain  name sub domain to "world wide
web".
We all know that domains names are registered keeping in mind either the  name of the company, or product,or service.e.g. A company based domain  name could be something like "Intel.com" or "hp.com" while a product  based or service based domain name could be like  "webhostingasia.blogspot.com" or even "gmail.com".
As discussed earlier that a domain contains a special componant in it  which tells the web browser about the type of web server a query is  seeking i.e. www.wallpaperdownload.biz could represent a web browser to  seek an html file. while ftp:wallpaperdownload.biz could mean to seek  ftp for document download. mail:wallpaperdownload.biz could mean to seek  an email server.
One important note here to make is that each of the domain names are seperated by a fullstop(.) mark.
 Domain Name RegistrationDomain registeration means to registering a name for your business, service or product online. Domain names registration
 have  become compulsary for both big business and small business. A business  or even a small firm could not even think of standing out in the market  without protecting their business name online. With more than a million  of domains registered daily it has become compulsary to secure the  business name online from our competitors since registering a domain  name could cost only from $4 to $20 dependimg on the domain extention  one decide to register for his/her business or firm.
What is the history of Domain name Registeration?The history of domain name registeration is just boggling to mind and I am sure it will boggle yours also when you gonna
 be reading the history of the daomain registeration.
The first domain and offcourse a TLD to get registered is  "symbolics.com". Symbolics.com was registered in 1985 by a computer  system firm in Massachusetts USA. But later sold to another party with  an undisclosed price.
By the passing of 1992 more than 1500 ".com" were on the internet. By  the end of december of 2009 there were more than 192 million domain  registered which consisted a large no of TLD ".com" which as of date  04\15\2010 were estimated to be 84 million domain names out of which  11.9 millions domains were online businesses and ecommerce web sites,  4.3 million domain names were of entertainment industry, 3.1 million  domain names dealing with finance and around 1.8 million web sites on  sports sector.
The latest records(july 2012) shocked everyone. There were more ".com"  TLD registered this year than all other domain registered this year in  together.