U.S. Patent No. 7,078,359 is directed to an aerogel composite with a fibrous batting (page 3). The claims recite a “lofty fibrous structure” or “lofty batting” (pages 3-4). While lofty is a term of degree, the specification provides an objective boundary (page 10). A “lofty batting” is expressly defined as “a fibrous material that shows the properties of bulk and some resilience (with or without full bulk recovery)” (page 10). Sufficiently resilient provides for compression to remove air (bulk) yet spring back to substantially the original size and shape (page 10). A batting is taught as being “lofty” if it “contains sufficiently few individual filaments (or fibers) [such] that it does not significantly alter the thermal properties of the reinforced composite as compared to a non-reinforced aerogel body of the same material” (page 10). Characteristics of loft batting (e.g., minimizes volume while avoiding thermal degradation and limited fibers in the Z-axis) are described (pages 10-11). Examples of commercial products that are lofty battings are described, including metrics (page 11). The prosecution history shows use of the specification description of loft batting, indicating definiteness of meaning (page 12). Lofty and batting are also terms of art (page 12). Like a case where a procedure or example guide the comparison, the specification provides sufficient guidance to render the claim term definite (pages 12-13). Using a term of degree in the definition does not change this (page 13). Teaching different ways to assess loftiness does not change this where the different ways do not result in confusion (page 14).
Hindsight: It may be useful to avoid using terms of degree to define a term of degree. Giving a definition with some criterion may be important. A numerical standard is the most clear, but describing characteristics, giving examples, and/or associating with a procedure may be sufficient.