HerryoudaoicibaDictYouDict[Herr 词源字典]
German equivalent of Mr., 1650s, originally "nobler, superior," from Middle High German herre, from Old High German herro, comparative of her "noble, worthy, exalted," from PIE *kei-, a color adjective, in suffixed form *koi-ro- here meaning "gray, hoary," hence "gray-haired, venerable." Cognate with Old Frisian hera, Dutch heer; perhaps in this usage a loan-translation of Latin senior. Hence also Herrenvolk "master race," in Nazi ideology, the concept of the German people.[Herr etymology, Herr origin, 英语词源]