Patent Cooperation Treaty (PCT)

Cross-referenced

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.

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.

Patent family

The set of related patents and applications that share a common priority claim — an original application plus its continuations, divisionals, and foreign counterparts. Members of a family typically share the same earliest filing (priority) date.

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 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 expiry

The point at which a patent's term ends and the invention enters the public domain — either at full term or early, when maintenance fees go unpaid. Once a patent expires, anyone may make, use, or sell what it covered: a drug patent expiring is what lets generic versions enter the market. Expired patents amount to a free, fully documented library of proven technology.