a diplomatic official of the highest rank, sent by one sovereign or state to another as its resident representative (ambassador extraordinary and plenipotentiary).
2.
a diplomatic official of the highest rank sent by a government to represent it on a temporary mission, as for negotiating a treaty.
3.
a diplomatic official serving as permanent head of a country's mission to the United Nations or some other international organization.
4.
an authorized messenger or representative. Abbreviation:Amb., amb.
Origin: 1325–75; ME am-, embass(i)adour, imbassadore < AF ambassateur, ambassaduer < It ambassatore, dial. It ambassadore, equiv. to ambass- (see embassy) -atore, -adore < L -ātōrem acc. of -ātor-ator
[am-bas-uh-der, -dawr] 
