Ambassador
late Middle English: from French ambassadeur, from Italian ambasciator, based on Latin ambactus ‘servant’.
wiktionary
From Middle English ambassadore, from Anglo-Norman ambassadeur, ambassateur, from Old Italian ambassatore, ambassadore, from Old Occitan ambaisador(“ambassador”), derivative of ambaissa(“service, mission, errand”), from MedievalLatin ambasiator, from Gothic 𐌰𐌽𐌳𐌱𐌰𐌷𐍄𐌹( andbahti, “service, function”), from Proto-Germanic *ambahtiją(“service, office”), derivative of Proto-Germanic *ambahtaz(“servant”), from Gaulish ambaxtos("servant"; also the source of Latin ambactus(“vassal, servant, dependent”)), from Proto-Celtic *ambaxtos(“servant”), from Proto-Indo-European *h₂m̥bʰi-h₂eǵ-(“drive around”), from *h₂m̥bʰi-(“around”) + *h₂eǵ-(“to drive”).
etymonline
ambassador (n.)
late 14c., also embassador, "diplomatic emissary of a ruler in the court of another," from Old French embassator, ambassateor, which comes via Provençal or Old Spanish from Latin ambactus "a servant, vassal," from Celtic amb(i)actos "a messenger, servant," from PIE root *ambhi- "around" + *ag- "to drive, draw out or forth, move."
Compare embassy. Forms in am- and em- were used indiscriminately in English 17c.-18c. Until 1893 the United States sent and received none, having only ministers (often called ambassadors), who represented the state, not the sovereign.
