Patent family

Cross-referenced

Claim

The numbered sentences at the end of a patent that define exactly what is legally protected. Claims are the only part of a patent that determine infringement — if a product or process doesn't fall within the scope of at least one claim, there is no infringement. Every other part of a patent (abstract, drawings, specification) exists to support and illuminate the claims.

Cross-referenced

Priority date

The date that determines whether a piece of prior art counts against a patent application. In the US, the priority date is typically the filing date of the earliest application in a patent family to which the current application claims priority. Under the first-to-file system (post-AIA), the inventor with the earliest priority date wins if two people file on the same invention.

Post-grant review (PGR)

A USPTO proceeding to challenge a recently granted patent, within nine months of grant, on almost any ground of invalidity — including eligibility and written description. It is broader than inter partes review, which is narrower and becomes available later.

Patent

A government-granted right that gives an inventor the exclusive right to prevent others from making, using, selling, or importing a patented invention within the country that granted the patent, for a limited time. A patent does not give the owner the right to practice the invention — only the right to exclude others. The US issues three types: utility, design, and plant patents.

Patent citation

A reference connecting two patents: the earlier patents and publications a patent cites as prior art (backward citations), and the later patents that cite it in turn (forward citations). Citations map the lineage of an idea — what an invention built on, and what was later built on it. A 2010 patent cited by 200 later patents is, by that measure, a foundational piece of its field.

Patent Cooperation Treaty (PCT)

An international treaty allowing inventors to file a single "PCT application" that preserves the right to seek patent protection in 150+ member countries. A PCT filing buys time — typically 30 months from the priority date — before the applicant must commit to specific national filings. It is not a "world patent"; each country still examines and grants its own patent under its own laws.