According to the patent law, " applicant may use terms in a manner contrary to or inconsistent with one or more of their ordinary meanings if the written description clearly redefines the terms." This has to be done by expressing such intentions in the patent application and providing custom definitions with reasonable clarity and precision. One way of achieving this is to include all definitions in the patent application, and ensuring that such terms are used while drafting claims as well. If I want to use highly abstract terms, invented by and unused in the field that my application relates to, how exactly should I technically do it in my application? How should I include all definitions in the patent application and where? And if I will do that and I will use these terms in my claims, are there any restrictions or risks associated with that? Is the right to be my own lexicographer recognized internationally in patent laws or just in U.S.?

3 Answers 3


Precise definitions are a risk. Real words have nuance and interpretation. If you have a concisely worded formal definition you have little leeway to argue later and can give an infringer a blueprint for designing around your claims. Something less than a formal definition might be a better approach.

  • Good point! One should give some consideration about whether to provide definitions, balancing unnecessary limitation against ensuring enablement.
    – Howlium
    Sep 8, 2020 at 22:12
  • In my description, some methods and elements of a system are given novel names, because the methods are mentioned many times in the description and so must be refered to somehow. They are simply so novel that no name exists for them. It's like using the term "chain of blocks" in Bitcoin whitepaper. The technology did no exist at the time, so some term, "chain" in this case, must have been coined. But I don't know if I should use a completely novel term in claims. Such a term covers all the elements and variations of method refered in description, because description always uses that term. But?
    – Leandro
    Sep 13, 2020 at 21:12
  • I would suggest at least one claim with the special term and one without. One way to do it is use the term in an independent claim and then in a dependent claim say - "The method of claim X where [special term] comprises . . . "
    – George White
    Sep 13, 2020 at 23:07
  • Did you mean to use special term in independent claim and not use it in dependent claim or the other way around? And what about just making two sets of claims, independent and dependent, one as "apparatus claims" and the other as "system" or "method" claims, while one set will use special term and the other not? I think it's the best coverage of claimed invention.
    – Leandro
    Sep 14, 2020 at 17:56
  • Going at the invention via differently structured claims is a good way to expand coverage and reduce ways for an infringer to get around you. In the U.S. you can have more than one independent claim per claim type so you could have all combinations. A dependent claim must be a narrowing of the claim it depends from so there is a constraint on where the special term is used.
    – George White
    Sep 15, 2020 at 16:55

The definition of special terms belongs in your Written Description. Then your Claims (which aren’t required for a provisional patent by the way) will be interpreted in view of the definitions in the description, as long as those definitions are clear to a PHOSITA (“person having ordinary skill in the art”).

If you litigate, there will be a claims construction phase. The only way I could imagine your custom definitions will not hold up is if they are contradictory or unclear, such that a PHOSITA would not understand them.

This will suffice internationally.

UPDATE: If you do define your own terms, or even if you use standard terms with some nuance, explicit definitions will be valuable to you in the event of infringement or invalidity litigation. You will save legal expense and increase the chance of a successful outcome in a Markman hearing (the courtroom proceeding that settles claim constructions). Explicit definitions will make it much harder for the opposing side to construe claim terms in a different way that may harm your position.

Disclaimer: I am not a lawyer.

  • Welcome to Ask Patents!
    – Eric S
    Sep 8, 2020 at 13:48

You can include definitions at the beginning of the patent application and use it subsequently. Dictionary words will always help in courts if you enforce your patent rights or if your patent validity is challenged.

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