sep
n. uncountable A1 Beginner US //ˈɛˈsiˈpi// sep
n. the short way to write September, which is the ninth month of the year.
n. the standard abbreviation for September, the ninth month of the Gregorian calendar. Usually written with a capital letter and often followed by a period.
The new school term begins in Sep.
The contract is scheduled to expire on 30 Sep, so we need to renew it soon.
Historical records indicate that the harvest festival was traditionally observed in mid-Sep, though the exact dates varied depending on the lunar cycle and local agricultural conditions.
Usage
Always capitalized as it is an abbreviation of a proper noun; often followed by a full stop (Sep.) in formal writing.