Definition - adv Or Adj [Medieval Latin, on behalf (of)] : on behalf of or involving only one party to a legal matter and in the absence of and usu. without notice to the other party <an ex parte motion> <relief granted ex parte> used in citations to indicate the party seeking judicial relief in a case <Ex Parte Jones, 7 U.S. 2 (1866)> compare in reinter partes Pronunciation'eks-'pär-tE, -tA