am·bas·sa·dor / amˈbasədər; -ˌdôr/ • n. an accredited diplomat sent by a country as its official representative to a foreign country: the French ambassador to Portugal. ∎  a person who acts as a representative or promoter of a specified activity: he is a good ambassador for the industry.DERIVATIVES: am·bas·sa·do·ri·al / amˌbasəˈdôrēəl/ adj.am·bas·sa·dor·ship / -ˌship/ n.

ambassador XIV. ME. ambassatour, -dour, em-, later with many vars. of sp.; the present sp. ambassador dates from XVI. orig. — various Rom. forms, (O)F. ambassadeur, etc.; all ult. resting on medL. ambactia mission, f. Gmc. *ambaxtija- (Goth. andbahti, OE. ambeht, OHG. ambaht(i), G. amt), f. *ambaxta-servant — L. ambactus, a Gaulish word *ambactos, prob. f. *amb- around + *ag- drive; see AMBI-, ACT, -OR1. Cf. EMBASSY.
Hence ambassadress XVI.

ambassador Diplomatic representative of the highest rank, appointed to represent a government abroad.