wikipedia.org is currently:
Domain name availability tells you if a domain name is registered or not. It may be useful to know the availability status of a domain name that you wish to register.
Checking if a domain name is available is easy, you simply enter the domain that you want to check into the whatsmydns.net domain availability checker tool and the status will be returned.
There are many reasons why you may want to check if a domain is available. Some of these reasons include:
Most domain names can be checked, however in some cases it is unknown for various technical reasons.