The following article appears in the journal JOM,
48 (9) (1996), pp. 77-79.

JOM is a publication of The Minerals, Metals & Materials Society

Understanding "Patentese"—A Patent Glossary

Arnold B. Silverman and George K. Stacey

All too frequently, intellectual property attorneys use patent jargon and, as a result, others are unable to understand. To reduce potential confusion, the following glossary provides general definitions of a number of frequently used patent terms with a view toward aiding in the comprehension of such terms. As space limitations preclude full delineation of all meanings, the definitions that follow should be regarded as providing accurate, but not exhaustive, meanings of the terms. Italicized words represent terms that are defined elsewhere in the glossary.


Active Inducement to Infringe: One may be held liable for patent infringement as a result of actively encouraging another to infringe if such other does infringe, even though the inducer has not made, used, sold, offered for sale, or imported the patented invention.

Apparatus Claim: This refers to a patent claim, which describes structurally a piece of equipment and is embraced by the expression "machine" in the definition of patentable subject matter in the U.S. Patent Statute.

Application: A written document seeking patent protection and filed with the U.S. Patent and Trademark Office or a patent office outside of the United States. In the United States, the application must include a disclosure of the invention that would, without undue experimentation, enable a person of ordinary skill in the art to make and use the invention; at least one claim; drawings (if drawings are necessary to understand the invention); and disclosure of what the inventor views as the best mode for practicing the invention. The claims of the application define the invention and the scope of the coverage sought. The written description and enabling disclosure are typically found in the specification portion of the application. The specification is the narrative portion of the application, along with the drawings, if present. The specification includes the description of the preferred embodiments or best mode of practicing the invention. It may include a summary of the invention; a description of the background of the invention, including prior art or the problem dealt with by the invention; and a description of the drawings. The specification may also include an abstract of the disclosure.

Apportionment of Profit: As a measure of damages in patent-infringement litigation, apportionment generally refers to dividing the profits on the sale of a particular piece of apparatus or a product according to the percentage of cost or sale price attributable to the patented invention and a portion not so attributable. In instances where the entire product is patented or the patented component contributes essentially all of the market value, such apportionment is not required.

Attorneys' Fees Award: In exceptional cases in patent infringement litigation, the court may require the losing party to pay the attorneys' fees of the prevailing party.

Best Mode: A patent application is required to disclose the best means known to the applicant of practicing the invention as of the date of filing the application.

Certificate of Correction: Issued upon patentee request due to a U.S. Patent and Trademark Office or applicant minor error in the patent such as printing, typographical, or clerical errors.

Claim(s): A claim is one of the numbered paragraphs that appear at the end of a patent and defines the scope of protection given to the owner of the patent (i.e., the right to prevent others from making, using, selling, offering for sale, or importing the claimed invention). Each claim is treated separately for purposes of determining validity and infringement. For example, claims may be directed toward apparatus, methods, products, and compositions of matter and new and useful improvements thereof.

Combining Prior Art: Under Section 102 of the U.S. Patent Statute, a claim must be identically disclosed in a single prior-art reference in order to be rejected as being anticipated by prior art. Under Section 103 of the Patent Statute (which deals with the standard of obviousness) one is permitted to employ a single prior art reference or combine two or more references to render a claim obvious if such a combination would be apparent to one skilled in the art. Under either standard, a patent application claim may be rejected by a patent examiner, or a patent claim may be ruled invalid by a court.

Comprising: The word "comprising" in a claim renders the claim open, which means that additional elements could be added to the accused infringing device without avoiding infringement. For example, if a claim stated that a chair had three legs and employed the word "comprising," a chair having four legs would infringe. At the other end of the spectrum is a closed claim, which uses the expression "consisting of." This means that in a product alleged to infringe, if meaningful additional elements are added to the features recited in a claim there is no infringement. These types of claims frequently appear in the chemical and metallurgical arts. There is an intermediate scope of claim that uses the expression "consisting essentially of" and means that some additional components may be employed in the allegedly infringing product without avoiding infringement.

Conception: This is the creation of the mental concept of the invention.

Constructive Reduction to Practice: A reduction to practice involves physical verification of the operability of the invention or its suitability for its intended purpose. When one files a U.S. patent application, one obtains a constructive reduction to practice as of the filing date.

Continuation Application: This is a patent application directed toward the same invention as a prior application and filed while the prior application is pending, naming the same inventive entity. The continuation application is given the benefit of the earlier filing date of the application on which it is based.

Continuation-in-Part Application: This is a continuation application that adds new matter to a previously filed copending application and need not name the identical inventive entity.

Contributory Infringement: This involves someone supplying a component that is a material part of a product, apparatus, composition of matter, or process with knowledge that it is uniquely adapted for use in infringing a patent and is not a staple article of commerce suitable for substantial noninfringing use. Such person can be held liable as a contributory infringer if an infringement results.

Copying: This generally refers to an infringer copying from a patented product, apparatus, composition, or process and may enhance evidence of infringement.

Critical Date: This refers to the date of the initial placing on sale, publication, or public or commercial use of an invention. At the end of the one-year period, a U.S. patent application cannot be filed because the statute bars such filing.

Crowded Art: This refers to an area of technology in which there have been a large number of prior inventions. In a crowded art, it takes less of an advancement to obtain a valid patent. Otherwise, one would have to conclude that there can be no further patenting in that art.

Dedication to the Public: A document signed by a patent owner filed in the U.S. Patent and Trademark Office giving up all patent rights. This is generally done when the owner believes the patent is invalid.

Dependent Claim: This is a claim that makes express reference to and depends on a prior claim and, thereby, incorporates by reference all of the recitals of the prior claim. This claim must be read as if it contained its own express recitals plus the recitals of every claim or claims from which it depends. Claims that do not depend from another are referred to as independent claims.

Design Patent: This type of patent covers the original and ornamental aspects of a product. The prime focus is on the overall ornamental appearance.

Disclaimer: When one or more patent claims (but not all of the claims) are invalid, the patentee may make a written disclaimer of such invalid claim or claims. A disclaimer is filed in the U.S. Patent and Trademark Office.

Disclosure: This can refer to either an invention disclosure that is not in a patent application but is an oral or written communication of a development or it can refer to portions of a patent application.

Divisional Application: A divisional application is a separate patent application carved out of a prior pending application and discloses and claims only subject matter originally claimed in the prior application. The divisional application is entitled to a priority or filing date based upon the application from which it has been divided.

Doctrine of Claim Differentiation: This is a judicially created rule of construction that states that when two claims in the same patent have an apparently similar or identical meaning, an effort should be made to adopt an interpretation that will give them a different (as distinguished from identical) meaning.

Doctrine of Equivalents: One literally infringes a claim where every element of the claim is expressly satisfied by a device, process, or composition of matter. Under the judicially created doctrine of equivalents, one may be held liable as an infringer even if one does not literally infringe a patent. In general, it is an equitable concept employed to prevent someone from getting the benefit of the invention by making a minor change that avoids literal infringement. See also the related concept of file wrapper estoppel.

Double Patenting: An inventive entity cannot obtain claims in two patents directed either to the same invention or to an obvious variation of the same invention. Where the inventions are identical, the second patent is invalid. With respect to obvious variations, this rejection can be overcome by filing a terminal disclaimer that, in effect, states that the second or any additional patents to issue will expire on the same date as the first patent, thereby eliminating any improper extension of the period of exclusivity resulting from the second or additional patents. A challenge based upon double patenting cannot be made where a second patent has issued as a result of a U.S. Patent and Trademark Office restriction requirement and the filing of a divisional application. In such a situation, the only reason more than one patent was issued is that the U.S. Patent and Trademark Office compelled limitation of a prior case to one embodiment.

Equivalents—Means-Plus-Function Claims: Rather than expressly reciting a component or feature in a patent claim, one may recite a feature as a means for accomplishing something such as "seal means for resisting passage of water between the bushing and the shaft."

Equivalents—Reverse Doctrine of: This concept is used infrequently. It refers to situations where one might literally infringe a patent claim, but due to the interpretation of the claim, would not be held to be an infringer.

Examiner: An employee of a patent office to whom an application is assigned for handling prosecution.

Exceptional Case: In order to seek an attorneys' fees award as part of the relief granted to the prevailing party in patent litigation, it is necessary to show that the case has unusual circumstances. In general, it means that there has either been willful infringement on the part of the alleged infringer or that the patentee was reckless in bringing an infringement case.

Experimental Use: Under Section 102(b) of the Patent Statute, there are a number of statutory bars which state that one cannot file a U.S. patent application more than one year after the initial placing on sale, publication, or public use of an invention. If the use was, in fact, experimental use rather than public or commercial use, such use is not counted in computing the one-year period. The experimentation must be to verify that the invention works for its intended purpose as distinguished from other factors such as marketing research.

Failure of Others: A secondary test of patentability relevant to the issue of whether an invention is obvious is whether others have failed to come up with the solution previously. Another way of expressing this concept is the existence of a long-standing and unsolved problem that tends to lend weight to patentability.

File Wrapper: This is the collection of documents located in the U.S. Patent and Trademark Office including a patent application and communications by the applicant and the U.S. Patent and Trademark Office with respect to the application.

File Wrapper Estoppel: When one amends an application during the course of prosecuting a patent application to overcome a prior art rejection by narrowing the claims, one is precluded or estopped from asserting a broader interpretation after the patent issues. This type of estoppel clearly exists in the face of a prior art rejection, but can also exist based upon comments made in writing by the applicant and any other representations, causing one to conclude that the U.S. Patent and Trademark Office relied on certain representations regarding scope of claim in allowing the application. Under current law, file wrapper estoppel does not necessarily totally preclude the use of the doctrine of equivalents in the assertion of an infringement claim, but does substantially restrict the application of the doctrine of equivalents. This is also referred to as prosecution history estoppel.

Fraud on the Patent and Trademark Office: This is now frequently referred to as inequitable conduct. An applicant and the applicant's attorney have an obligation to acquaint the U.S. Patent and Trademark Office with any prior art known to be material to the patentability of the patent application claims. There is no requirement that the applicant perform a patentability search. The standard is merely one of sharing knowledge. One is generally not required to identify art that would be merely cumulative.

GATT: The General Agreement on Tariffs and Trade signed by President Clinton on December 8, 1994. One resulting change is that a U.S. patent, if granted on an application filed on or after June 8, 1995, will have a term measured by 20 years from the filing date rather than the prior standard of 17 years from the date the patent was granted. Patents in force on June 8, 1995, and applications filed before that date will have a term that is the longer of these two terms. GATT also provided for provisional applications.

Gist of the Invention: This may also be referred to as the "heart of the invention." It refers to what are the novel and unique features of the claimed invention.

How to Make: This is part of the obligation to provide a disclosure in the patent application that would enable one skilled in the art to practice the invention without engaging in undue experimentation.

How to Use: This is a similar standard to the "how-to-make" standard and relates to the use aspect of an invention, if appropriate.

Hypothetical Person Skilled in the Art: The standard applied under Section 103 of the Patent Statute is whether the invention would have been obvious at the time the invention was made to one having ordinary skill in the art. One must look at the nature of the technology and determine what sort of individual would be skilled in the art. There are no rigid standards that are employed in making such a determination. For example, if the invention involved an automobile transmission, a mechanical engineer working on transmission design, a mechanic working on automobile transmissions, a mechanical engineering professor, or others could be a "person skilled in the art."

Improvement Patent: This generally refers to a patent that is issued on an application filed later in time than a prior application and tends to build upon the previously disclosed invention or the previously disclosed and claimed invention.

Indefiniteness of Claim: Section 112 of the Patent Statute requires that the claims be sufficiently definite so as to provide a standard by which a third party could, with some degree of certainty, determine whether a given practice would or would not be an infringement of the claims.

Independent Claim: This is a claim that stands by itself and must be so read in terms of infringement and validity evaluations. This is contrasted with a dependent claim.

Infringement: Someone who makes, uses, sells, places on sale, or imports into the United States a claimed invention is guilty of infringement. There can be direct or literal infringement, infringement under the doctrine of equivalents, contributory infringement, and active inducement to infringe.

Interference: A multiparty priority proceeding in the U.S. Patent and Trademark Office wherein two or more parties claim the same invention. The parties present evidence of conception and reduction to practice with a view toward proving who first invented the subject matter of the claims involved in the interference.

Invention: In the United States, in order to have a patentable invention, one must have a development that is useful, novel (no single prior art reference shows the identical development), and unobvious to one skilled in the art at the time the invention was made, which is assumed to be the filing date of the patent application.

Inventive Entity: This refers to the inventor or inventors named in a patent application or patent.

Inventor: One who contributes to the conception and reduction to practice of one or more of the claims in a patent application or patent.

Jepson Claim: This is a claim form wherein the preamble acknowledges the prior art teachings. The words "the improvement comprising" or "the improvement consisting of" or "the improvement consisting essentially of" are generally employed to form a border between the preamble and the body of the claim. It is followed in the body of the claim by what is believed to be unique.

Literal Infringement: This means that a product, process, apparatus, or composition of matter satisfies every recital of a claim literally.

Long-Felt Need: This means a problem facing a particular technical area that has gone unsolved for a prolonged period. The presumption is if the solution had been obvious to those skilled in the art, they would have solved the problem.

Lost Profits: This is a measure of damages and is generally keyed to the profits that could have been the patentee's, but were lost to the infringer. The alternate standard, where the patentee is either not in the business or cannot prove that profits made by the infringer would have been his or hers, is to employ the standard of the statute that is not less than a reasonable royalty.

Maintenance Fees: In the United States, maintenance fees or taxes must be paid at 3.5, 7.5, and 11.5 years after issuance of a patent in order to maintain the patent in force.

New Matter: Subject matter that was not present in the original application as filed cannot be added to a pending patent application by amendment.

Notice (Also Marking): Placing the word "patent" with the patent number on articles made by the patentee or a licensee. If the patentee fails to mark his or her products, then the patentee may recover only damages for infringement that occurred after the infringer has received actual notice through a charge of patent infringement.

Notice of Allowance: A written communication from the U.S. Patent and Trademark Office indicating that a patent application has been allowed.

Notice of Appeal: A document filed by the applicant in the U.S. Patent and Trademark Office to initiate an appeal of an examiner's rejection to the Board of Patent Appeals and Interferences.

Novelty: One of the conditions that an invention must meet in order to be patentable. Novelty is present if no single piece of prior art discloses every element of the claimed invention.

Obviousness: If the invention could readily be deduced at the time the invention was made from publicly available information (prior art) by a person of ordinary skill in that art, it is obvious. Prior art may be combined to show that an invention would have been obvious. (For example, the teachings of two or more prior art patents or a prior art patent and a prior art article may be combined). If an invention would have been obvious to a person of ordinary skill in the art at the time the invention was made, then it is not patentable.

Obvious to Try: The validity of a patent can be challenged by attempting to show that what the inventor did would have been obvious to try based on the prior art, and, therefore, the invention would have been obvious.

Office Action: An official written communication from an examiner in the U.S. Patent and Trademark Office giving the position of the U.S. Patent and Trademark Office on a pending patent application. After receiving an adverse office action, the applicant must respond within the set time limits.

On Sale: If an inventor places his or her invention on sale more than one year before a U.S. patent application is filed, then a valid patent cannot be obtained. This is sometimes referred to as the on-sale bar to a patent. An invention is on sale where it has actually been sold or an offer of sale has been made.

Ordinary Skill in the Art: The level of technical knowledge, experience, and expertise possessed by the run-of-the-mill or ordinary engineer, scientist, or designer in the technology that is relevant to the invention. Obviousness is measured with reference to a hypothetical person having ordinary skill in the art to which the invention pertains.

Patent: A grant by the federal government to an inventor of the right to exclude others from making, using, selling, offering for sale, or importing a patented invention. Patents that cover structural or functional aspects of products, composition, and processes are utility patents. Other types of patents include design patents covering ornamental designs of useful objects and plant patents covering new varieties of living plants.

Patentee: The inventor to whom the patent is granted and all persons to whom the patent is subsequently assigned. The term is slightly broader than the owner of the patent as the inventor would still be considered a patentee even if he or she has assigned his or her invention to someone else.

Preamble: The formal introductory clause of a patent claim. Depending on the circumstances, the preamble may or may not define a narrowing element of the claim. The preamble usually only defines the setting or context in which the elements of the claim appear. As a Jepson claim preamble sets forth the setting of the new invention, the use of Jepson format results in an implied admission that what is recited in the preamble is known in the prior art.

Preferred Embodiment: The preferred embodiment of an invention can usually be interpreted as being recited as the best mode known to the inventor of carrying out the invention.

Prejudgment Interest: In patent litigation, prejudgment interest is interest on monetary judgment against an infringer awarded to a prevailing party measured from the date of the infringement to the date of the judgment. Prejudgment interest should be available on damages measured both by lost profits and reasonable royalty.

Presumption of Validity: A presumption created by statute that a patent is legitimate and sound-in-law. The burden of establishing that a patent is invalid is always on the challenger. The burden of proof on the challenger is to prove invalidity by clear and convincing evidence.

Prior Art: The existing body of technological information against which an invention is judged to determine if it is patentable as being novel and unobvious. It must be early enough in time to be cited against the application.

Prior-Art Statement: Also known as an information disclosure statement, this is a document filed in the U.S. Patent and Trademark Office by the applicant during the prosecution of a patent application. The statement lists the prior art known by the applicant and/or his or her attorneys that is thought by them to be material to the patentability of the claims.

Profits: Direct recovery of the patent infringer's profits is not possible in a case of infringement of a utility patent, but may, under proper circumstances, be employed as a measure of the patentee's damages.

Provisional Application: As a result of GATT, an applicant can file a patent specification complying with U.S. disclosure standards and get the filing date as a priority date for a complete patent application filed within one year thereafter claiming the benefit. The provisional application does not have to contain claims. The effective filing date of the full application for purposes of avoiding prior art will be the filing date of the provisional application, but will have the benefit of the date of filing the full application for purposes of the 20 year patent term.

Prosecution: The administrative process of obtaining a patent from the U.S. Patent and Trademark Office. Prosecution includes filing the application with the U.S. Patent and Trademark Office, office actions, amending the application in response to objections and rejections from the examiner, responding to objections and rejections without amendment to the application, telephone and personal interviews with the examiner, appeals, and timely payment of the appropriate fees.

Prosecution History Estoppel: This is synonymous with file wrapper estoppel.

Public Use: A public or commercial use of an invention. If the public use occurred more than one year before the filing date of the patent application, obtaining a U.S. patent would be barred. If a use is experimental, then it is not a public use. Sometimes experimental use is referred to an exception to the public-use bar.

Reduction to Practice: The physical part of the inventive process that completes the process of invention. Until there is a reduction of practice, there is no invention. There are two kinds of reduction of practice: Constructive reduction to practice occurs upon the filing of a U.S. patent application that adequately discloses the invention. Constructive reduction to practice does not involve any physical construction. Actual reduction to practice occurs when there is physical verification that the invention works for the intended purpose. The reduction to practice must involve each and every element that is defined as constituting the invention. The degree of physical verification required will depend on the nature and complexity of the invention.

Reissue: An application filed by a patentee after a patent has issued to correct applicant's errors that rendered the patent wholly or partly inoperative due to a defective specification or drawings or which claimed more or less than the applicant had a right to claim. The applicant must provisionally surrender the previously issued patent. Any reissue patent that results will have the same expiration date as the original patent.

Rejection: A ruling by an examiner in an office action that one or more claims are not allowed.

Request for Reexamination: A request filed by a patentee or a third party seeking reexamination of one or more claims of a patent based upon an alleged substantial new issue of patentability due to printed prior art not considered by the U.S. Patent and Trademark Office examiner who handled the application originally.

Restriction Requirement: This occurs when an examiner concludes that a patent application claims two or more independent and distinct inventions. The restriction requirement, if made final, requires the applicant to elect to pursue one group of claims in the application in which the requirement is made. The nonelected claims may be pursued by a divisional application.

Royalty (Reasonable Royalty): A hypothetical royalty fee used as a measure of damages to compensate for the infringement of a patent. It is the statutory minimum amount of recovery for compensatory damages for patent infringement.

Secondary Considerations: Objective evidence of the actual marketplace setting in which an invention was made. This evidence is relevant to deciding whether an invention is unobvious. Categories of such evidence would include commercial success of the claimed invention, long-felt need that was met by the invention, unexpected results achieved by the invention, failure of others to make the invention, and copying of the invention by others.

Skill in the Art: An ordinary level of proficiency in a particular technology in which an invention is made.

Specification: The part of the patent application that precedes the claims and in which the inventor specifies, describes, illustrates, and discloses the invention in detail.

Teach: To inform and instruct by way of the documents making up the prior art. The prior art references teach the technology disclosed in them or revealed by them.

Teach Toward—Teach Away: A prior-art reference that suggests or points in the direction of the present invention is said to teach toward the invention and is evidence that the invention is obvious. A prior-art reference that diverges and points in a technical direction away from the present invention is evidence that the invention is unobvious. Prior art must be looked at in its entirety.

Terminal Disclaimer: Where an obviousness-type double patenting rejection has occurred, an applicant may file a document indicating that the term of the second patent will end upon expiration of the first patent to issue.

That Which Infringes if Later, Anticipates if Earlier: A rule stating the equivalence between two tests under patent law (i.e., the test of infringement of a patent and the test of anticipation in the prior art to invalidate a patent). If the claim of a patent is literally infringed by a prior art reference, then the claim is anticipated by that prior art reference and, therefore, is unpatentable. Note that there cannot be anticipation of a claim by equivalents.

Willful Infringement: Conduct that constitutes an illegal use of another's patented invention where the infringer has no reasonable basis for believing that its actions are legal (i.e., infringement when the infringer knew of the patent and had no reasonable basis for believing that it either did not infringe the patent or that the patent was invalid or unenforceable). A finding of willful infringement is a basis for increasing damages up to treble the actual amount and/or the award of attorneys' fees to the prevailing party. Good-faith reliance on the advice of counsel can be relevant to the issue of whether an infringement was willful.

Arnold B. Silverman is a partner in the law firm Eckert Seamans Cherin & Mellott in Pittsburgh, Pennsylvania, and George K. Stacey is patent counsel with Smith & Nephew North America.

For more information, contact A.B. Silverman at Eckert Seamans Cherin & Mellott, 600 Grant Street, 42nd Floor, Pittsburgh, Pennsylvania 15219; (412) 566-6000; fax (412) 566-6099; e-mail ARNIE@TELERAMA.LM.COM.

Copyright © 1996 by The Minerals, Metals & Materials Society.

Direct questions about this or any other JOM page to jom@tms.org.

Search TMS Document Center Material Matters Contents JOM TMS OnLine