EuphratesyoudaoicibaDictYouDict[Euphrates 词源字典]
Mesopotamian river, arising in Armenia and flowing to the Persian Gulf, Old English Eufrate, from Greek Euphrates, from Old Persian Ufratu, perhaps from Avestan huperethuua "good to cross over," from hu- "good" + peretu- "ford." But Kent says "probably a popular etymologizing in O.P. of a local non-Iranian name" ["Old Persian," p.176]. In Akkadian, purattu. Related: Euphratean.[Euphrates etymology, Euphrates origin, 英语词源]