The very first word that comes to our mind while thinking for our own website, blog or forum is of Domain. Many of the starters have declined their ideas on Domain as they couldn't found the right name for their websites. But this is something that should not be done.

Before we get close to more terminologies related to the domain lets start with 'What a Domain Is?'. A DOMAIN is the name that represents your online work or your online presence. It is the name that contains all your work. All your work that you are planning to show or share over internet is given the name of a Domain.
For Businessmen a Domain is the name of their Business and they want to have their domain name under their Business Name or an Abbreviation of their Business Name.
For BLOGGERS a domain represents their work. A name that reflects what they are talking about.
Some people selects a domain name that is fully connected to their business / work and some choose a totally different domain name that is not even related to their business/work.

A domain has two parts: THE NAME and THE EXTENSION.

THE NAME: It is that part that takes your most of the time deciding 'which one'? For example in the domain: " www.google.com" Google is the NAME part. This NAME part, while deciding your website's name should not be too lengthy or too short to memorize. It should not be too 'tacky' or too 'simple' that you can't find it available.

THE EXTENSION: Now this part is where your name selection gets stuck mostly. Before knowing more on EXTENSIONS please take a look at the available Domain TLD's.TLD means: 'Top Level Domain'
Domain TLDs are not just 'anything to choose' but have specific meaning. But the most common used worldwide is .COM.
There are two types of domain TLDs: G-TLD and CC-TLD. G-TLD means the 'Generic TLD' and CC-TLD means 'Country Code TLD'.
Under Generic TLD comes .com, .net, ,org, .asia etc. CC-TLD covers TLDs that represents specific countries like .us(US domain). .de(Deutschland/Germany), uk(United Kingdom).

Before you can select for any one TLD (generic or country-code) you must first decide as to what is your purpose and where your website will be more visible and visited. Let's suppose if you are having your business scattered in India then your TLD should be .in(India) that represents that the website contains the details of business offerings by that company in INDIA.
You can also use .COM as your TLD. Though there is as such no issue with the gTLD but before going for any ccTLD think before selecting them as you may have to file some documentations before going with any ccTLD.

Check various TLDs and their meanings here.