What is the legal term for the unauthorized use of a trademark or service mark?

The legal term for the unauthorized use of a trademark or service mark is trademark infringement. This occurs when a party uses a mark that is identical or confusingly similar to a registered trademark in a manner that is likely to cause confusion among consumers about the source of the goods or services. The essence of trademark law is to protect the distinctive signs that identify and distinguish goods or services, ensuring that consumers can reliably know who is providing them.

In the context of the options provided, other terms like patent violation and copyright breach refer to different areas of intellectual property rights. Patent violations involve unauthorized use of patented inventions or processes, while copyright breaches relate to unauthorized use of creative works, such as literature, music, or art. Brand misuse is not a recognized legal term and does not specifically encompass the unauthorized use of trademarks. Hence, trademark infringement is the most accurate and relevant term for the unauthorized use of a trademark or service mark.