Domain names cannot be copyrighted as they are not considered to be creative works. However, a domain name can still be protected under trademark law if it is used in commerce, represents a brand, and someone else can reasonably argue that your use of the domain name creates confusion with their brand. To check if a domain name is already registered as a trademark, you can search the U.S. Patent and Trademark Office’s trademark database, or consult with a qualified legal professional.