Patent term

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Design patent

A patent covering the ornamental appearance of a functional object — its shape, configuration, or visual design — not how it works. Design patents last 15 years from grant. They are faster and less expensive to obtain than utility patents. Apple's US D618,677 patent on the iPhone's rounded-rectangle shape is a famous example; it was central to over $1 billion in damages against Samsung.

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Maintenance fees

Periodic fees that must be paid to the USPTO to keep a granted utility patent in force. For US utility patents, fees are due at 3.5 years, 7.5 years, and 11.5 years after grant. If a fee is missed, the patent expires. Many patents go abandoned not because the invention was worthless, but because the owner decided the cost of maintenance wasn't justified by the remaining commercial value.

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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.

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Public domain

The status of an invention (or creative work) that is no longer — or never was — protected by any intellectual property rights, meaning anyone can use it freely. Patents enter the public domain after expiration (typically 20 years from filing for utility patents). Expired patents represent a vast, free library of technology available to all. Many foundational technologies — aspirin, the original CRISPR patents — have entered or are approaching the public domain.

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Terminal disclaimer

A document filed with the USPTO in which a patent applicant agrees that the term of a patent will end no later than the expiration of an earlier related patent. Terminal disclaimers are commonly required to overcome an "obviousness-type double patenting" rejection — which occurs when two related patents claim inventions that aren't patentably distinct from each other.

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Utility patent

The most common type of US patent, covering inventions that have a useful function — how something works, how it is made, or how it is used. Utility patents account for roughly 90% of all US patents issued. They last 20 years from the filing date of the non-provisional application, subject to payment of maintenance fees. Software, medical devices, chemical processes, and mechanical inventions are all protectable as utility patents.