Trademark: A name, symbol, or, other device identifying a product officially registered and legally restricted to the use of the owner or manufacture.
Trademark ® registration is critical to fully protect trademarks and service marks.  Domain names must be registered to maximize protection and to deter unwanted and unauthorized use of the name by others.  Obtaining a domain name alone does not offer trademark protection.
A trademark costs several hundred dollars to prepare and to file.  They have the potential to last as long as the mark is used in interstate commerce.  The United States Patent and Trademark Office processing fee is $325 or less if filed electronically or $375 for a paper-filed application, per international class.