early 15c., "case which may be taken as a rule in similar cases," from Middle French precedent, noun use of an adjective, from Latin praecedentum (nominative praecedens), present participle of praecedere "go before" (see precede). Meaning "thing or person that goes before another" is attested from mid-15c. As an adjective in English from c.1400. As a verb meaning "to furnish with a precedent" from 1610s, now only in past participle precedented.
A previous ruling by a court that influences subsequent decisions in cases with similar issues.