# 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.

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

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

---

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