What are Definition Notes in the USPC?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

Definition Notes in the United States Patent Classification (USPC) are explanatory notes that accompany class and subclass definitions. According to MPEP 902.02(a), these notes are of two types:

• Supplementary notes: These “supplement definitions by explaining terms or giving examples.”
• “See or Search” notes: These refer to “related disclosures located in other classes or subclasses” and are “helpful in explaining the limits of a class or subclass.”

These notes are crucial for understanding the scope and boundaries of patent classifications.