Mediatize \Me"di*a*tize\, v. t. [imp. & p. p. {Mediatized}; p. pr. & vb. n. {Mediatizing}.] [Cf. F. m['e]diatiser.] To cause to act through an agent or to hold a subordinate position; to annex; -- specifically applied to the annexation during the former German empire of a smaller German state to a larger, while allowing it a nominal sovereignty, and its prince his rank. The misfortune of being a mediatized prince. --Beaconsfield.