# Backward citation

An earlier patent or publication that a given patent cites as part of its prior-art foundation — listed on the patent's front page as "references cited." Backward citations show what an invention built upon: a drone patent might cite earlier flight-control patents. Some references come from the applicant, others are added by the examiner during the prior-art search. The opposite of a forward citation.

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

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

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