All the best names were already taken long ago (I understand every word in the dictionary has a domain name) you have to be creative to come up with an effective name no one else has thought up.
There are sites with tools that help you come up with fictitious names, including: wordlab.com, naming.net, wordoid.com, lingzini.com, namestation.com, domainsBot.com some of these tools look up the domain name availability as you go.
If you find an available .com name, there's a high probability that it' not a trademarked name.
u creating a website. it depends upon which category u can tell me i wiil suggest u.
www.google.com
it depends upon the category. please let us know the category.then we will suggest
