SeptemberyoudaoicibaDictYouDict[September 词源字典]
September: [11] September is etymologically the ‘seventh’ month. The word comes from Latin September, a derivative of septem ‘seven’ (the Roman year started with March). Other English descendants of Latin septem, which is a distant relative of English seven, include septet [19] and septuagenarian [18].
=> seven[September etymology, September origin, 英语词源]
SeptemberyoudaoicibaDictYouDict
late Old English, from Latin September (also source of Old French Septembre, Spanish Setiembre, Italian Settembre, German September), from septem "seven" (see seven). So called because it was the seventh month of the old Roman calendar, which began the year in March; Julian calendar reform (46 B.C.E.) shifted the new year back two months. For -ber suffix, see December. Replaced Old English hærfestmonað, haligmonað. Related: Septembral.