The United States Patent and Trademark Office (USPTO) grants patents for the protection of inventions and registers trademarks.
A trademark is a word, name, symbol, or device that is used in trade with goods to indicate the source of the goods and to distinguish them from the goods of others. Trademark rights may be used to prevent others from using a confusingly similar mark, but not to prevent others from making the same goods or from selling the same goods or services under a clearly different mark.
Registered trademarks refer to trademarks that have been registered by the United States Patent and Trademark Office (USPTO) and they are the only trademarks registered to use the 'r' symbol.
State trademarks are trademarks that have been registered by a state, not the USPTO. State trademarks are only valid in the states where they are registered and they use the TM symbol. The Secretary of State is the entity in charge of trademarks for Illinois.
Common law trademarks are trademarks that have not been registered by the USPTO, nor have they been registered in any state. It is not necessary to register a trademark. You can establish legal rights simply by using the trademark in commerce. These trademarks also use the TM symbol.
