" AMBASSADOUR  (AMBA'SSADOUR)   n.s.[ambassadeur, Fr. embaxador, Span. It is written differently, as it is supposed to come from the French or Spanish language; and the original derivation being uncertain, it is not easy to settle its orthography.Some derive it from the Hebrew , to tell, and , a messenger; others from ambactus, which, in the old Gaulish, signified a servant; whence ambascia, in low Latin, is found to signify service, and ambasciator, a servant; others deduce it from ambacht, in old   Teutonick, signifying a government, and Junius mentions a possibility of its descent from amab  and others from am for ad, and bassus, low, as supposing the act "

― Samuel Johnson , A Dictionary of the English Language (Complete and Unabridged in Two Volumes), Volume One