RES JUDICATA

Lat.: a thing decided; a matter adjudged. The phrase reflects a rule by which a final judgment by a court of competent jurisdiction is conclusive upon the parties in any subsequent litigation involving the same cause of action.

see bar; merger. EXAMPLE: Two parties litigate an issue in one federal disctrict court, and the defendant loses. Under the principle of res judicata, the defendant could not then go to another federal district court and litigate the same issue a second time.

Compare collateral [COLLATERAL ESTOPPEL]. Source: Barron's Dictionary of Legal Terms, Steven H. Gifis, 5th Edition; © 2016