Trademarks are defined in the Lanham Act as a word, name, symbol, or device or any combination thereof which is used to identify and distinguish the goods of one person from goods manufactured or sold by others and to indicate the source of the goods of, even if the source is unknown to the consumer. The TM symbol is used to identify a potential trademark and the symbol is used to identify a registered trademark. A potential trademark is a mark which the Patent and Trademark Office has yet to grant trademark protection. Once the Patent and Trademark Office has granted a trademark, the mark is considered a registered trademark. The SM symbol is used for service marks which the Patent and Trademark Office has yet to grant trademark protection.
Service marks are similar to trademarks but are used to identify a service instead of goods.
Once the Patent and Trademark Office has granted a service mark, the mark is considered a registered service mark. Displaying a TM or SM indicates to others that the owner of the mark believes his or her mark is worthy of protection. In addition, marking may help prevent others from using similar marks. As for registered marks, an owner should display a registered mark symbol because the symbol provides appropriate notice to potential infringers. By failing to provide notice of a registered mark, the owner cannot recover profits or damages from an infringer, unless the defendant has actual notice of the registration.