ThursdayyoudaoicibaDictYouDict[Thursday 词源字典]
Thursday: [OE] The Romans called the fourth day of the week diēs Iovis ‘Jupiter’s day’. When the Germanic peoples took over their system of naming days after the gods, or the planets they represented, they replaced Jupiter, the Roman sky-god, with the Germanic god of thunder, Thor, whose name comes from the same source as English thunder. This produced a prehistoric Germanic *thonaras daga-, which evolved into Old English thunresdæg. The modern form Thursday is partly due to association with Old Norse thórsdagr.
=> thunder[Thursday etymology, Thursday origin, 英语词源]
Thursday (n.)youdaoicibaDictYouDict
fifth day of the week, Old English þurresdæg, a contraction (perhaps influenced by Old Norse þorsdagr) of þunresdæg, literally "Thor's day," from Þunre, genitive of Þunor "Thor" (see thunder (n.)); from Proto-Germanic *thonaras daga (cognates: Old Frisian thunresdei, Middle Dutch donresdach, Dutch donderdag, Old High German Donares tag, German Donnerstag, Danish and Swedish Torsdag "Thursday"), a loan-translation of Latin Jovis dies "day of Jupiter."

Roman Jupiter was identified with the Germanic Thor. The Latin word is the source of Italian giovedi, Old French juesdi, French jeudi, Spanish jueves, and is itself a loan-translation of Greek dios hemera "the day of Zeus."