september

noun

1. the ninth month of the year, containing 30 days. Abbreviation: Sept., Sep.

noun

1. the ninth month of the year, consisting of 30 days

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.