The U.S. Supreme Court case Nautilus, Inc. v. Biosig Instruments, Inc., 2013 revolved around the issue of patent definiteness under 35 U.S.C §112(b). Biosig had patented a heart rate monitor for use during exercise and sued Nautilus alleging infringement of their patent rights. The District Court initially ruled in favor of Nautilus stating that the claim was indefinite as it did not clearly define what constituted "spaced relationship" between electrodes on the device which is crucial to its functioning. However, this decision was reversed by Federal Circuit court applying 'insolubly ambiguous' standard meaning if a claim is not insoluble then it's definite enough to be valid. Nautilus appealed against this decision arguing that such an interpretation allows patents with vague claims thus hindering innovation and competition while promoting unnecessary litigation. The Supreme Court agreed with Nautilus ruling that a patent must provide clear notice of what is claimed thereby demanding precision but also acknowledging some level of uncertainty due to inherent limitations in language itself. It rejected ‘insolubly ambiguous’ standard set by Federal Circuit court instead introducing new one: A patent’s claims are regarded as indefinite if they fail to inform those skilled in art about scope of invention with reasonable certainty at time when patent application was filed.

In the Supreme Court case of Nautilus, Inc. v. Biosig Instruments, Inc., there was no formal dissenting opinion as the decision was unanimous. The court ruled in favor of Nautilus and held that a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent and the prosecution history, fail to inform those skilled in the art about what is claimed with reasonable certainty. This ruling rejected both parties' proposed standards for definiteness and clarified how courts should approach this issue moving forward.