What makes a claim indefinite when using relative terms?

A claim using relative terms may be rendered indefinite when the scope of the term is not understood when read in light of the specification. The MPEP 2173.05(b) states: “Even if the specification uses the same term of degree as in the claim, a rejection is proper if the scope of the term is not understood when read in light of the specification.” Additionally, when relative terms are used in claims where the improvement over the prior art rests entirely upon size or weight of an element, the adequacy of the disclosure of a standard becomes more critical.

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• indefiniteness
• relative terms
• claim interpretation
• patent claims