Patent Glossary: Essential Terms Every Inventor Should Know

Patent law has its own language. This glossary defines the essential terms you will encounter when filing, reading, or challenging patents, in plain English.

A–C

Abstract — A short summary (typically 150 words or fewer) on the front page of a published patent. It describes the technical problem and the gist of the solution but carries no legal weight when interpreting claims.

Anticipation — When a single prior art reference discloses every element of a patent claim, that claim is “anticipated” and invalid for lack of novelty under 35 U.S.C. §102. If you need two or more references to cover all the elements, the analysis shifts from anticipation to obviousness.

Assignee — The entity that owns the patent rights. Inventors are the original owners but frequently assign rights to an employer or company. The assignee is listed on the patent’s front page.

Claims — The legal boundaries of a patent, written in numbered paragraphs at the end of the specification. Everything else in the document exists to support and explain the claims. If you only read one part of a patent, read the claims. See understanding patent claims for a deeper breakdown.

Continuation — A follow-on application that claims the same priority date as the parent but pursues different claims. Continuations let an applicant carve out additional protection from the same disclosure without adding new subject matter.

Continuation-in-Part (CIP) — Like a continuation, but a CIP adds new matter not in the parent application. The new matter only gets the CIP’s own filing date, not the parent’s priority date.

CPC (Cooperative Patent Classification) — A hierarchical classification system jointly developed by the USPTO and EPO. Every patent is assigned one or more CPC codes describing its technology area. CPC codes are more granular than the older IPC system and are the primary tool for classification-based searching.

D–F

Dependent Claim — A claim that references and narrows an earlier claim by adding at least one limitation. Dependent claims provide fallback positions: if the broader independent claim is invalidated, narrower dependent claims may survive.

Description/Specification — The detailed written portion of a patent that explains the invention in enough detail that someone skilled in the field could reproduce it. In USPTO practice, the specification includes the title, background, summary, detailed description, drawings, and claims.

Design Patent — A patent protecting the ornamental appearance of a functional article, not its utility. In the US, design patents filed on or after May 13, 2015 last 15 years from issuance with no maintenance fees (earlier filings have a 14-year term). The European equivalent is a registered design.

Divisional Application — Filed when an examiner determines that a single application claims more than one distinct invention. The applicant keeps one invention in the original filing and moves the others into separate divisionals, each retaining the parent’s priority date.

Doctrine of Equivalents — A legal doctrine extending infringement beyond literal claim language. A product can infringe even without literally meeting every claim element, if it performs substantially the same function, in substantially the same way, to achieve substantially the same result.

Effective Filing Date — The earliest date from which a patent application can claim priority. For applications claiming priority from a provisional, continuation, or foreign filing, this reaches back to the earliest qualifying application. This date determines what counts as prior art against the claims.

Examiner — The patent office official who reviews an application, searches for prior art, evaluates claims for novelty and non-obviousness, and issues office actions when problems arise. In the US, examiners work within technology-specific art units at the USPTO.

FTO (Freedom-to-Operate) — An analysis determining whether a product would infringe any active patent claims in a target jurisdiction. An FTO maps your product’s features against the claims of relevant patents to quantify risk. See freedom-to-operate analysis for a detailed walkthrough.

G–I

Grace Period — A window during which an inventor’s own public disclosure does not count as prior art against their application. In the US, this is 12 months (35 U.S.C. §102(b)(1)). The EPO has no general grace period, applying absolute novelty under EPC Art. 54.

Grant — The formal issuance of a patent by a patent office. Once granted, the holder can enforce the claims against infringers. At the EPO, grant is followed by a nine-month window during which third parties can file an opposition to challenge the patent’s validity (EPC Art. 99).

IDS (Information Disclosure Statement) — A submission to the USPTO listing prior art and other information material to patentability that is known to the applicant, governed by 37 C.F.R. §§1.97 and 1.98. The underlying duty of disclosure arises under 37 C.F.R. §1.56. Breach of that duty can support an inequitable conduct defense, which under Therasense v. Becton, Dickinson (Fed. Cir. 2011, en banc) requires proof of but-for materiality and specific intent to deceive. Where established, inequitable conduct renders the entire patent unenforceable.

Independent Claim — A claim that stands on its own without referencing any other claim, defining the broadest scope of protection. Most patents have one to three independent claims. Every dependent claim traces back to an independent claim.

Infringement — The unauthorized making, using, selling, offering for sale, or importing of a patented invention within the jurisdiction where the patent is active. If every element of at least one claim is present in the accused product, there is literal infringement.

Inter Partes Review (IPR) — A proceeding before the US Patent Trial and Appeal Board (PTAB) challenging claim validity based on prior art patents or printed publications. Created by the America Invents Act (enacted 2011, effective September 16, 2012), IPR is faster (12 to 18 months) and cheaper than district court litigation. It has become the primary mechanism for invalidating weak patents.

International Searching Authority (ISA) — The patent office that conducts the prior art search for a PCT international application and issues a written opinion on novelty and inventive step. The ISA’s opinion is non-binding but heavily influences national phase examination.

Inventive Step — The EPO term for what US law calls “non-obviousness.” Under EPC Art. 56, an invention has an inventive step if it is not obvious to a person skilled in the art. The EPO applies the “problem-solution approach,” which differs from the US framework.

Inventor — The natural person who conceived the invention. Only human beings can be named as inventors (the DABUS AI cases confirmed this in the US and UK). Inventorship is a legal determination, and getting it wrong can invalidate the patent.

IPC (International Patent Classification) — A WIPO-maintained classification system organizing patents by technology area. IPC codes are assigned to every patent published worldwide. CPC has largely replaced IPC for searching purposes, but IPC remains the universal baseline.

J–N

Kind Code — A letter-number suffix on a patent publication number identifying the document type. “A1” typically indicates a published application, “B2” a granted patent. Kind codes vary by country. For a detailed breakdown, see patent number formats.

Lapse — When a patent ceases to be in force because the holder failed to pay maintenance fees or take a required action. A lapsed patent enters the public domain.

Maintenance Fee — Periodic fees required to keep a granted patent in force. In the US, these are due at 3.5, 7.5, and 11.5 years after grant. At the EPO, annual renewal fees begin during prosecution. Failure to pay results in lapse.

Markman Hearing — A pretrial hearing in US patent litigation where the court interprets disputed claim terms. Named after Markman v. Westview Instruments (1996). Claim construction here often determines the outcome of the entire case.

Means-plus-Function — A claim drafting style permitted under 35 U.S.C. §112(f) where an element is described by its function rather than its structure (“means for fastening” instead of “a bolt”). Courts interpret these elements narrowly, limiting scope to the structures disclosed in the specification and their equivalents.

National Phase — The stage at which a PCT international application enters individual countries for examination and potential grant. Applicants typically have 30 or 31 months from the priority date to enter. Each country then examines under its own patent law.

Non-Obviousness — Under 35 U.S.C. §103, a patent cannot be granted if the invention would have been obvious to a person of ordinary skill given the prior art. The Supreme Court’s KSR v. Teleflex (2007) broadened the grounds for obviousness rejections by making it easier for examiners to combine multiple references.

Non-Patent Literature (NPL) — Any prior art reference that is not a patent document: academic papers, conference proceedings, technical standards, dissertations, blog posts. NPL is frequently overlooked in searches, but examiners cite it regularly, especially in software, biotech, and materials science.

Novelty — The requirement that an invention must be new. Under 35 U.S.C. §102, an invention lacks novelty if it was previously patented, described in a publication, in public use, on sale, or otherwise available to the public before the effective filing date.

O–P

Office Action — A written communication from a patent examiner setting out rejections or requirements for a pending application. Applicants respond by amending claims, submitting arguments, or both. Most applications receive at least one office action before grant.

Patent Family — A group of patent applications and grants sharing a common priority filing. Analyzing patent families reveals where an invention is protected geographically and how claims evolved across jurisdictions.

Patent Landscape — A broad survey of patent activity in a technology area, company portfolio, or region. Landscapes aggregate data from hundreds or thousands of patents to identify trends, white spaces, and key players.

Patent Prosecution — The back-and-forth between an applicant and the patent office from filing to grant or abandonment, including responding to office actions, amending claims, and filing continuations. The term has nothing to do with criminal law.

PCT (Patent Cooperation Treaty) — An international treaty administered by WIPO allowing applicants to file a single international application designating over 155 countries. The PCT does not grant patents. It provides a unified filing and search process before the application enters national phase for substantive examination.

Prior Art — Any evidence that an invention was already known before the patent’s effective filing date, including patents, academic papers, product manuals, public demonstrations, and conference talks. Prior art is the foundation of both patentability analysis and patent invalidation. For a full treatment, see what is prior art.

Priority Date — The date of the earliest application from which a later filing claims priority. Under the Paris Convention, an applicant who files in one country has 12 months to file elsewhere while retaining the original priority date. This date determines what qualifies as prior art.

Provisional Application — A US-specific filing that establishes a priority date without starting the patent term clock. A provisional is not examined and expires after 12 months unless a non-provisional is filed claiming its benefit. Useful for securing an early date while the invention is still being developed.

Publication Number — The unique identifier assigned to a patent document when published (e.g., US-2024/0123456-A1). Each publication event gets its own number and kind code. For a guide to reading these, see patent number formats.

Q–S

Reduction to Practice — The point at which an invention moves from concept to working reality. “Actual” reduction means building and testing a working embodiment. “Constructive” reduction means filing a patent application with sufficient detail. Under first-to-file, constructive reduction (filing) is what matters.

Reexamination — A USPTO proceeding reconsidering the patentability of claims based on prior art. Ex parte reexamination can be requested by anyone. Inter partes reexamination was eliminated by the America Invents Act effective September 16, 2012, and replaced by Inter Partes Review (IPR) before the PTAB.

Reissue — A procedure to correct errors in a granted patent. A reissue can broaden, narrow, or correct claims, but broadening must be filed within two years of grant. The reissued patent retains the original expiration date.

Restriction Requirement — An examiner’s determination that an application claims two or more distinct inventions. The applicant must elect one for prosecution and may file divisional applications for the rest.

Scope — The extent of protection defined by the patent claims. Broad scope covers a wide range of implementations. Narrow scope is limited to specific configurations. Scope is determined by claim language, prosecution history, and judicial construction.

Specification — The complete written description of the invention, including title, field, background, summary, detailed description, and drawings. The specification must satisfy the written description, enablement, and best mode requirements of 35 U.S.C. §112.

Standard Essential Patent (SEP) — A patent claiming technology necessary to implement an industry standard (e.g., 5G, Wi-Fi, HEVC). SEP holders who participate in standard-setting organizations typically commit to licensing on fair, reasonable, and non-discriminatory (FRAND) terms.

T–Z

Trade Secret — Confidential business information that derives value from not being publicly known. Trade secrets are an alternative to patents: you keep the invention secret indefinitely instead of disclosing it for a limited monopoly. The tradeoff is no protection against independent discovery or reverse engineering.

Transitional Phrase — The linking language between the preamble and body of a patent claim. “Comprising” (open-ended), “consisting of” (closed), and “consisting essentially of” (allows non-material additions) are the three standard phrases. The choice dramatically affects claim scope.

Unity of Invention — The EPO and PCT equivalent of the US restriction requirement. Under PCT Rule 13, a single application must relate to one invention or a group linked by a “special technical feature.”

Utility Model — A form of patent protection available in some jurisdictions (Germany, China, Japan, South Korea) but not in the US or UK. Sometimes called “petty patents,” they have shorter terms (typically up to 10 years), lower inventive step requirements, and faster registration without substantive examination in most jurisdictions.

Utility Patent — The most common type of patent, protecting new and useful processes, machines, articles of manufacture, or compositions of matter. In the US, utility patents have a 20-year term from the earliest non-provisional filing date (35 U.S.C. §154). For guidance on reading one, see how to read a patent.

WIPO (World Intellectual Property Organization) — The United Nations agency administering the PCT, the Madrid Protocol (trademarks), the Hague System (designs), and the IPC classification system. WIPO does not grant patents but provides the international infrastructure connecting national patent offices.

Written Description Requirement — Under 35 U.S.C. §112(a), the specification must show that the inventor actually possessed the invention at the time of filing. This is distinct from enablement (which asks whether someone skilled in the art could make and use it). It prevents applicants from claiming more than they actually invented.

Explore patents on GoVeda — see these terms in context →