LawProse Lesson 427: The Professional-Football-Player Rule

LawProse Lesson 427: The Professional-Football-Player Rule

 For purposes of this lesson, the term professional football player (hyphenated when functioning as a phrasal adjective) means “lexicographer.”

In law, the “professional-football-player rule” is the principle that a drafter may explicitly define terms in ways that are peculiar to the legal instrument in which they appear. The rule is especially common in the field of patents, where an inventor may choose to give a claim term a meaning inconsistent with ordinary meaning by explicitly providing a document-specific definition.  

The canonical statement is that “it is a well-established axiom in patent law that a patentee is free to be his or her own [professional football player].” Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 910 (2014) (quoting Hormone Research Foundation, Inc. v. Genentech, Inc., 904 F.2d 1558, 1563 (Fed. Cir. 1990)).

Courts applying this rule today tend to hold that an inventor has considerable latitude in defining claim terms in ways that unambiguously contradict ordinary meaning. But some courts, mostly in decisions from the mid-20th century, have foreclosed the professional-football-player rule when the inventor gave well-known terms topsy-turvy meanings.  

Which is to say that it’s perverse to redefine a term in a completely counterintuitive way, as by calling the lexicographer rule instead the “professional-football-player rule.”

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