<p><strong>Noun:</strong></p><ul><li>a diplomatic official of the highest rank, sent by one sovereign or state to another as its resident representative ambassador extraordinary and plenipotentiary.</li><li>a diplomatic official of the highest rank sent by a government to represent it on a temporary mission, as for negotiating a treaty.</li><li>a diplomatic official serving as permanent head of a country's mission to the United Nations or some other international organization.</li><li>an authorized messenger or representative.</li><li>Amb., amb.</li></ul>