Patent law glossary — IHatePatentTrolls

Quick reference for the patent-law vocabulary used across this site. Each definition is one or two sentences; the deeper treatment lives in the linked article. Articles deep-link into individual entries with /resources/glossary#term-slug.

Jump to: A · B · C · D · E · F · G · H · I · K · L · M · N · O · P · R · S · T · U · V · W

A

Abstract idea: One of the three judicial exceptions to § 101 patent eligibility (alongside laws of nature and natural phenomena). Includes fundamental economic practices, mathematical relationships, and methods of organizing human activity. See Bilski v. Kappos and Alice v. CLS Bank.
America Invents Act (AIA): The 2011 statute that switched the U.S. to a first-inventor-to-file system and created IPR, PGR, and CBM as adversarial USPTO post-grant proceedings. Full article: the AIA.
Anticipation: A § 102 invalidity theory: a single prior-art reference discloses every limitation of a claim. Distinct from obviousness, which combines references. See § 102 prior art.
Asserter: Anyone making a patent infringement demand against you — the entity behind the demand letter or lawsuit. Often a shell NPE rather than the original inventor or assignee.

B

Business-method patent: A patent claiming a way of doing business — financial transactions, advertising, etc. Survived Bilski as a category but is uniquely vulnerable to § 101 abstract-idea challenges.

C

Covered Business Method review (CBM): An AIA-era post-grant proceeding for financial-services method patents. Sunset in 2020; replaced in practice by PGR and IPR. See patent reviews.
Continuation-in-part (CIP): A continuation application that adds new subject matter to the parent's disclosure. Older subject matter retains the parent's priority date; new matter gets only the CIP's filing date.
Claim: The numbered sentence(s) at the end of a patent that legally define what's protected. The only part of a patent a court enforces. See how to read a patent claim.
Claim chart: A side-by-side table mapping each claim limitation to evidence in an accused product (for infringement) or a prior-art reference (for invalidity). The standard format for both offensive and defensive analyses.
Claim construction: The court's interpretation of disputed claim terms. A question of law for the judge under Markman; the resulting order governs the rest of the case.
Claim limitation: One of the requirements listed in a claim. To infringe, an accused product must have every limitation; to anticipate, a prior-art reference must disclose every limitation.
Continuation: A child patent application that shares the parent's specification and priority date but pursues different claim scope. The reason most asserted patents have siblings still in prosecution.

D

Declaratory judgment (DJ): A lawsuit filed by a potential infringer asking the court to declare the patent invalid or not infringed. Useful when a demand letter creates real apprehension of suit but the patent owner hasn't actually sued.
Demand letter: A pre-litigation letter accusing infringement and (usually) demanding a license payment. The standard opening move in NPE assertions. See if you get a demand letter.
Dependent claim: A claim that incorporates by reference all the limitations of another claim and adds at least one more. Strictly narrower than the claim it depends on.
Divisional: A child application split off from a parent in response to a restriction requirement. Independent claim scope, same parent priority date.
Doctrine of equivalents (DOE): A theory that an accused product can infringe even without literally meeting every claim limitation, when the differences are "insubstantial." Limited by prosecution history estoppel under Festo.

E

Examiner: The USPTO official who reviews a patent application, issues office actions, and ultimately allows or rejects claims.
Exceptional case: A case in which the loser pays the winner's attorney's fees under § 285. The standard was loosened by Octane Fitness — abusive NPE behavior frequently qualifies.

F

Federal Circuit: The U.S. Court of Appeals with exclusive jurisdiction over patent appeals. All district-court patent rulings and PTAB final written decisions go here. Geographic circuits don't hear patent appeals.
Festo presumption: The rebuttable presumption that a narrowing claim amendment during prosecution surrenders all equivalents in the surrendered scope. Three rebuttals: unforeseeability, tangential rationale, and "some other reason." See Festo.
File wrapper: The complete prosecution history of a patent — the application, every office action, every applicant response, every amendment. Public via PAIR/PEDS. Often the most useful single record in a claim construction or DOE fight.
Final Written Decision (FWD): The PTAB's final ruling on the merits at the end of an IPR or PGR. Triggers IPR estoppel for the petitioner.
Forum shopping: Choosing a litigation venue to gain a procedural or substantive advantage. The Eastern District of Texas was the dominant patent forum until TC Heartland restricted "resides" to the state of incorporation.

G

Graham factors: The four-step framework for obviousness analysis from Graham v. John Deere (1966): scope of prior art, differences from the claims, level of ordinary skill, and secondary considerations. Survived KSR intact.

H

Hindsight reasoning: An obviousness rebuttal: combining prior-art elements that look obvious only after the patent disclosed the combination. Courts are skeptical of the argument post-KSR, but it still wins occasionally.

I

Independent claim: A claim that doesn't reference any other claim. Usually broader than the dependent claims that build on it. Patent litigation typically starts with the independent claims.
Inequitable conduct: An unenforceability defense: the patentee withheld material information from the USPTO with intent to deceive. Successful inequitable-conduct findings render the patent unenforceable. The bar tightened sharply after Therasense (Fed. Cir. 2011).
Infringement: Making, using, selling, offering to sell, or importing a patented invention without authorization. Literal infringement requires every claim limitation; equivalents infringement uses the doctrine of equivalents.
Inter Partes Review (IPR): An adversarial post-grant proceeding at the PTAB, available 9 months after issuance for any patent. Petitioners attack validity under § 102 and § 103 only — no § 101 at the PTAB. See patent reviews and the cost.
IPR estoppel: The rule that an IPR petitioner can't later raise in district court any invalidity ground the petitioner raised, or reasonably could have raised, in the IPR. Significant strategic risk. See IPR estoppel.
Inventive concept: The "something more" required at Step 2 of the Mayo/Alice framework — the claim element or combination that transforms an abstract idea into a patent-eligible application. Generic computer implementation doesn't qualify.

K

KSR rationale: A flexible motivation-to-combine theory under KSR v. Teleflex: common sense, design need, predictable variation, or market pressure can supply the obviousness rationale, in addition to the older TSM test.

L

Limitation: See claim limitation.
Litigation funding: Third-party financing of a plaintiff's case in exchange for a share of any recovery. Common in NPE assertions; raises § 285 exposure questions when discovery into the funder is allowed.

M

Machine-or-transformation test: An older Federal Circuit § 101 test: a process is patent-eligible only if it's tied to a particular machine or transforms an article into a different state. Rejected as the sole test in Bilski, but still a "useful clue."
Markman hearing: A pretrial hearing where the court construes disputed claim terms. The resulting order governs the rest of the case — often deciding infringement and validity in advance of trial. See Markman v. Westview.
Mayo/Alice framework: The two-step § 101 test: (Step 1) is the claim directed to a judicial exception?, and (Step 2) does the claim contain an "inventive concept" beyond the exception? Articulated in Mayo; extended to abstract ideas in Alice.
Means-plus-function: A claim format ("means for [doing X]") that imports the corresponding structure from the specification under § 112(f). Construed narrowly — limited to disclosed embodiments and equivalents.

N

Narrowing amendment: A claim amendment during prosecution that reduces claim scope, usually to overcome a prior-art rejection. Triggers the Festo presumption of prosecution history estoppel.
Non-Practicing Entity (NPE): A patent owner that doesn't make or sell products covered by the patent — its only revenue source is licensing or litigation. Often pejoratively called a patent troll. See what is a patent troll.

O

Obviousness: The § 103 invalidity theory: the claimed invention would have been obvious to a PHOSITA at the time, given the combined prior art. The workhorse defense. See § 103 obviousness and KSR.
Office action: The USPTO examiner's written response to an application — typically rejecting some or all claims under § 102, § 103, § 112, or § 101. The applicant has a fixed period to respond with arguments or amendments.

P

Patent family: A patent and all its continuations, divisionals, CIPs, and foreign equivalents that share a common priority claim. Most asserted patents have siblings still in prosecution.
Patent troll: An NPE that asserts low-quality patents primarily to extract settlements below the cost of defense. Distinct from legitimate licensing entities. See how patent trolls operate.
Post-Grant Review (PGR): An adversarial PTAB proceeding available only in the first 9 months after a patent issues. Broader than IPR: petitioners can raise § 101 and § 112 grounds, not just § 102 and § 103.
PHOSITA: Person Having Ordinary Skill in the Art. The hypothetical baseline reader of a patent and prior art — the lens for both obviousness and claim construction. Education + experience common to the field at the priority date.
Pleading stage: The earliest phase of a lawsuit — before discovery — when the parties argue whether the complaint states a valid claim. The cheapest place to win a § 101 motion if the patent is clearly an abstract idea.
Prior art: Anything that was publicly known before the patent's priority date — patents, publications, products, public uses. The fuel for § 102 anticipation and § 103 obviousness attacks. See § 102 prior art.
Priority date: The earliest date the patent gets to claim. Determines which references count as prior art. Earlier priority dates protect against more prior art; later priority dates expose the patent to more.
Prosecution: The back-and-forth between the patent applicant and the USPTO — applications, office actions, responses, amendments — culminating in either issuance or abandonment. See how to obtain a patent.
Prosecution history estoppel (PHE): The doctrine that surrendered claim scope during prosecution can't be reclaimed under the doctrine of equivalents. Today governed by the rebuttable Festo presumption.
Patent Trial and Appeal Board (PTAB): The USPTO's tribunal that hears IPR, PGR, and ex parte appeals. Created by the AIA in 2011. Three administrative patent judges sit on each panel.

R

Reasonable royalty: The minimum measure of damages under § 284 — what a willing licensor and willing licensee would have agreed to in a hypothetical negotiation. The default damages theory in most cases lacking lost-profits proof.
Reexamination: An ex parte USPTO proceeding to re-examine a patent's validity under § 102 and § 103, based on prior-art patents and printed publications. Pre-AIA tool, still available; less powerful than IPR.
Regular and established place of business: The second prong of the patent venue statute, § 1400(b). Per In re Cray (Fed. Cir. 2017), requires an actual physical place where the defendant employs people doing its work. Sublease + remote workers ≠ enough.
Restriction requirement: An examiner's demand that an applicant elect one of multiple distinct inventions in a single application. Drives the creation of divisional applications.

S

Secondary considerations: Indirect evidence of non-obviousness: commercial success, long-felt need, failure of others, copying, industry praise, unexpected results. Always relevant but rarely outcome-determinative on its own.
§ 101 (Section 101): The patent-eligibility statute. Excludes laws of nature, natural phenomena, and abstract ideas. The framework for software- and business-method-patent challenges. See Alice, Mayo, and Bilski.
§ 102 (Section 102): The novelty / anticipation statute. A claim is anticipated if a single prior-art reference discloses every limitation. See § 102 prior art.
§ 103 (Section 103): The non-obviousness statute. A claim is obvious if the differences between the claim and the prior art would have been obvious to a PHOSITA. See § 103 obviousness and KSR.
§ 112 (Section 112): The specification statute. § 112(a) requires written description and enablement; § 112(b) requires definite claims; § 112(f) governs means-plus-function claims.
§ 285 (Section 285): The fee-shifting statute. Permits a court to award attorney's fees to the prevailing party in exceptional cases. Loosened by Octane Fitness. See § 285 fee shifting.
§ 1400(b) (28 U.S.C.): The patent venue statute. Permits suit only "where the defendant resides" or "where the defendant has committed acts of infringement and has a regular and established place of business." Restricted by TC Heartland.
Shell company: A holding entity created solely to assert a single patent or small portfolio. Used by NPEs to limit financial exposure and obscure ownership. See shell-company examples.
Specification: The descriptive portion of a patent — text, figures, examples — that supports and contextualizes the claims. Must enable a PHOSITA to make and use the invention. Dictionary for claim construction.
Summary judgment: A motion under Rule 56 asking the court to decide a claim or defense without trial because there's no genuine issue of material fact. Common stage for invalidity and non-infringement rulings.

T

Tangential rationale: One of three Festo rebuttals to prosecution history estoppel: the reason for the narrowing amendment bears no more than a tangential relation to the equivalent in question.
TC Heartland: The 2017 Supreme Court decision restricting patent venue: a domestic corporation "resides" only in its state of incorporation under § 1400(b). Ended the Eastern District of Texas dominance. See the full article.
Terminal disclaimer: A statement filed during prosecution disclaiming any term beyond a related patent's expiration. Used to overcome obviousness-type double-patenting rejections; ties the disclaimed patent's term to its parent's. See patent term and expiration.
Teaching, suggestion, motivation (TSM): The pre-KSR Federal Circuit obviousness test, which required the prior art itself to teach, suggest, or motivate the combination. Still a valid rationale post-KSR, but no longer required.
Two-step framework: See Mayo/Alice framework.

U

Unforeseeability: One of three Festo rebuttals to prosecution history estoppel: the equivalent at issue was unforeseeable at the time of the narrowing amendment.
USPTO: United States Patent and Trademark Office. The agency that examines and grants patents, hosts the PTAB, and maintains the public prosecution-history records.

V

Venue: The judicial district where a lawsuit can be brought. For patent cases, governed by § 1400(b) and reshaped by TC Heartland.

W

Willful infringement: Infringement with knowledge that the activity infringed a valid patent. A finding of willfulness allows enhanced damages up to 3× under § 284 and supports an exceptional case finding under § 285.

This glossary intentionally stays brief — for the full doctrinal treatment of any term linked above, follow the article link. Suggest a missing term by emailing hello@ihatepatenttrolls.com.

This article is for general education and is not legal advice.