# 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.

**Full entry:** https://patentbrief.org/glossary/patent-expiry

**All patent terms:** https://patentbrief.org/glossary

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_Source: PatentBrief — https://patentbrief.org. A plain-English glossary of US patent terms._