are Terms of “Degree” Indefinite Claim Language Under 35 U.S.C. 112?

MARK TERRY, ESQ.

Terms of degree—such as “easily,” “readily,” and “aesthetically pleasing”—can be subjective and therefore problematic when used in patent claims. The Federal Circuit’s decision in Hearing Components, Inc. v. Shure Inc. provides guidance for using this language without triggering an indefiniteness rejection under 35 U.S.C. §112.

The definiteness requirement asks whether the claims, read in light of the specification, notify the public of the scope of the patentee’s right to exclude. A claim is not required to define an invention with mathematical precision, but a person skilled in the relevant art must be able to understand what is claimed.

Not every term of degree is indefinite. The specification must, however, provide a standard for measuring the degree. Courts therefore look to the written description to determine whether a phrase that appears subjective has an objective or understandable boundary.

The practical lesson is that terms of degree may be used when the specification explains how to measure them. For example, a specification using “easily connected” could explain that the phrase means two components can be joined manually, such as through a snap-fit connection, without tools or mechanical equipment.