Patent Application Drafting: Using the Specification for more than the ordinary plain meaning

You may have heard that it is inappropriate to read into a patent claim from the specification. That isn’t entirely accurate, although you will hear that popular misconception often repeated even by some patent professionals. At best the statement is only half correct.

It is true that you cannot impermissibly read from the specification into a patent claim. Obviously, when you add the critical term “impermissibly” into the mix that has to mean that there are times when it is appropriate to read into a patent claim from the specification, which is indeed true. In fact, there is no blanket prohibition against reading into a patent claim from the specification. The trick, obviously, is to know when it is permissible and when it is impermissible.

Before we can address this question head on allow me to take a step back to fill in two gaps.

First, the term “specification” as being used here relates to the written disclosure that makes up that patent application and is not a part of the patent claims or Abstract. The specification (i.e., the written description) will include a description of the invention and of the manner and process of making and using the invention in full, clear, and exact terms such that those skilled in the technology field or science to which the invention pertains will be able to make and use the invention. The specification must also completely describe at least one specific embodiment of the invention, whether the invention is a process, machine, manufacture, composition of matter or improvement thereof, and must explain the mode of operation or principle of operation wherever possible.


Second, any patent, or patent application, contains a variety of different sections that contain different, albeit redundant information. Generally speaking, a patent is divided into a specification, drawings and patent claims. Only the patent claims define the exclusive right granted to the patent applicant. The rest of the patent is there to facilitate understanding of the invention articulated in the patent claims — which is referred to as the claimed invention. Therefore, patent claims are in many respects the most important part of the patent application because it is these claims that define the invention for which the Patent Office has granted, or will grant, protection.

Before proceeding let’s initially answer the pending question: Can you read into a patent claim from the specification? The answer is yes. The point of the specification is to act as a dictionary or glossary for the patent claims. You absolutely can define terms and concepts in the specification and those meanings will be imported into the claims. What you cannot do, however, is fail to incorporate an element or characterization into the claim and then point to it in the specification and say it is implicitly in the claims. You read definitions into the claims, which requires the claim having at least a placeholder that refers back to the specification. You cannot forget to include something in the claim and save yourself because it is in the specification.

With that out of the way, let’s take another step back and fill in some more gaps again.

The whole purpose of the specification, as already briefly mentioned, is to facilitate understanding of the claimed invention. Indeed, in a patent application you can define the terms you will use in the patent claims to provide the meaning you specifically intend. This specifically defined meaning will apply during any claim interpretation, whether that claim interpretation takes place during patent prosecution with the patent examiner or once the patent has issued.  But what happens when you do not define a term in the specification?  Well, that really depends.  As a general rule the ordinary plain meaning of the term as would be understood by someone of skill in the relevant technology area or science will be used. That may or may not be bad, and it may or may not be what you intended.

This issue came up several years ago during the patent war between Apple and Motorola, Judge Richard Posner of the United States Court of Appeals for the Seventh Circuit issued a ruling, while sitting by designation as a trial judge.  See Apple v. Motorola No. 1:11-cv-08540 (N.D. IL., Jan. 17, 2012). Motorola had argued that Apple’s U.S. Patent No. 7,479,949 was invalid because it used the term “heuristic,” thereby rendering the claims invalid as being indefinite and in violation of 35 U.S.C. 112(b). In fact, the term “heuristic” was used well over 100 times in the ‘949 patent, but it wasn’t ever specifically defined.


Motorola’s primary evidence of indefiniteness consisted of statements in various depositions taken during discovery.  The nine listed inventors were deposed and most of them conceded that the term “heuristics” is “sort of a vague word.”  They were also unable to suggest an appropriate definition.  Nevertheless, Judge Posner agreed that the definition of heuristics provided by Apple for purpose of claim construction was appropriate and keeping with the patent disclosure.  Apple defined “heuristics” to mean “one or more rules to be applied to data to assist in drawing inferences from the data.” This is certainly a reasonable definition, but it was not provided in the patent application filed.

Judge Posner, citing Solomon v. Kimberly-Clark Corp., 216 F.3d 1372, 1379 (Fed. Cir. 2000), explained that it is inappropriate to consider inventor testimony when assessing validity under section 112(b).  For the uninitiated that may seem odd, but the question isn’t whether inventors or even someone of skill in the relevant technology area can define any particular term in a vacuum. Rather, the question is whether the invention is particularly defined in the specification and whether someone of skill in the relevant technology or science who read the specification would understand.  In essence, the inquiry is one of a totality of circumstances based on the law, with an eye toward what was disclosed in the specification. If you read the ‘949 patent it is clear that the term “heuristic” was being use by the attorneys who wrote the application to mean one or more rules. But the lesson for our purposes is this: When you do not define the terms you use in a patent application itself it can be an expensive and unpredictable process to get to the meaning that will be ultimately be accepted by the court.

Judge Posner ultimately decided that the term “heuristics” as used in the specification of the ‘949 patent was entirely consistent with the definition provided by Apple. Of course, this would not have been an issue if Apple had defined the term “heuristic” in the patent application. This is not to suggest that the attorneys representing Apple made a mistake, hindsight is always 20-20 and the context of how they were using the word “heuristic” does seem abundantly clear, but rather this story should be illustrative of why it is best practice whenever possible to define what you specifically want understood by the terms and concepts you use in a patent application.

When I teach this topic the example I tend to use relates to “standard room temperature.” If you have invented a process that needs to be carried out at 68 degrees F you might say that the process can or should be carried out at standard room temperature, for example. In the U.S. standard room temperature is generally referred to as 20 degrees C, which is 68 degrees F. But in some parts of the world what qualifies as standard room temperature is a bit warmer, sometimes up to 25 degrees C. So this illustration is particularly useful for several reasons. When you say standard room temperature did you even know that it has an accepted meaning in the scientific community? Were you aware that the meaning could vary depending upon whether the person reading the disclosure is in the United States or some other part of the world? This is where defining what you mean could be particularly important.

Let’s assume for a minute that the process will work from 19 degrees C to 24 degrees C, but not over 24 degrees C or under 19 degrees C. If you simply say “at standard room temperature” that is not precise enough, and indeed inaccurate (at worst) or confusing (at best). But could you define “standard room temperature” as being between 19 degrees C and 24 degrees C? Absolutely! Generally speaking, the Manual of Patent Examining Procedures explains that an applicant is entitled to be his or her own lexicographer, giving their preferred meaning by clearly setting forth a definition of the term or concept.  This can allow the applicant to even give meanings to terms that are somewhat different from the ordinary and customary meaning(s), although you can’t define terms so that they are diametrically opposite to their ordinary plain meaning.  See e.g. MPEP 2111.01.  So you couldn’t say, “when I say ‘up’ I mean ‘down’ and when I say ‘down’ I mean ‘up’.”

So what if you said something like this: “The process should be carried out at between 19 degrees C to 24 degrees C, which is sometimes in this disclosure referred to as standard room temperature.” That would be perfectly fine. Moreover, if you then used the term “standard room temperature” in the claims you would be importing that definition provided (i.e., between 19 degreesC  to 24 degrees C).

If you do not define terms in the specification then they are given their ordinary plain meaning as would be understood by one of skill in the relevant technology area or science. So returning to our example of “standard room temperature,” if you did not define the range you wanted to be considered as “standard room temperature” and just used that term in the claims there would be difficult questions to answer. You could pretty much guarantee that an argument would be made that standard room temperature means nothing more than 20 to 25 degrees C, which capture temperatures that won’t work, but not all that do work. You might even have to deal with an argument that standard room temperature is only 20 degrees C because, after all the application was filed in the United States so the meaning as understood in the U.S. should govern. Therefore, defining terms and concepts can be particularly important.


Additional Information

For more tutorial information please see Invention to Patent 101: Everything You Need to Know. For more information specifically on patent application drafting please see:



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