What is a Serial Number in the context of trademark applications?

In the context of trademark applications, a Serial Number serves as a unique identifier assigned by the USPTO to each trademark application. This number is crucial because it allows applicants, the USPTO, and the public to easily track and reference the specific application throughout the examination process and beyond. Each trademark application is assigned a different Serial Number, ensuring that there is no confusion between different applications, even if they are similar in nature.

The other options do not accurately represent what a Serial Number signifies. While application denial, filing fee identifiers, and extension dates are relevant to the trademark application process, they do not describe the function or purpose of a Serial Number. Instead, they refer to different aspects of trademark application management and procedures, emphasizing the distinctive role that the Serial Number plays in identifying and monitoring the status of individual applications.