How can applicants respond to indefiniteness rejections?

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.

Applicants have several options to respond to indefiniteness rejections. The MPEP outlines these approaches:

“In response to an examiner’s rejection for indefiniteness, an applicant may resolve the ambiguity by amending the claim, or by providing a persuasive explanation on the record that a person of ordinary skill in the relevant art would not consider the claim language unclear.”

Applicants can respond by:

• Amending the claim to clarify the language
• Providing a persuasive explanation of why the claim is definite
• Submitting evidence, such as declarations from experts in the field
• Providing a separate definition (e.g., from an art-recognized dictionary)
• Explaining how the term is used in the context of the invention

It’s important for applicants to address all points raised in the rejection and provide clear arguments or amendments to overcome the indefiniteness issues.