A more thorough explanation:

The Supplemental Register is a list of trademarks maintained by the United States Patent and Trademark Office (USPTO). It is a secondary register that provides limited trademark rights and benefits. Trademarks that do not qualify for the Principal Register are placed on the Supplemental Register. These marks are usually non-distinctive and lack secondary meaning, meaning that consumers do not associate them with a specific source.

For example, if a business uses a descriptive trademark to market their goods or services, such as "Great Burgers," "Sweet Treats," or "Super Shoes," these words are not unique and do not qualify for the Principal Register. Therefore, they would be placed on the Supplemental Register.

Benefits of using the Supplemental Register include:

• The ability to use the registered sign (®) or language such as "Reg. U.S. Pat. Off." to protect from trademark infringement
• Permission to register the trademark outside the United States, as long as that country offers similar trademark rights and protections
• The right to collect money, relief, or damages if you win an infringement lawsuit

In summary, the Supplemental Register is a list of trademarks that do not qualify for the Principal Register due to their lack of distinctiveness and secondary meaning. Businesses can still benefit from trademark protection by registering on the Supplemental Register and using the registered sign to protect their brand.