(rare) Characteristic of September.

The ninth month of the Gregorian calendar, following August and preceding October. Abbreviations: Sep or Sep., Sept or Sept. / (rare) A female or male given name from English.

plural of September

Happening in the middle of September.

In the middle of September.

Any time in the middle of September.

The terrorist attacks that took place in the United States on September 11, 2001.

The terrorist attacks that happened on September 11, 2001.

(Internet slang, historical) A period beginning around 1993, in which large amounts of new users were joining Usenet.

(astronomy) The moment when the sun crosses the celestial equator while heading southward, occurring on September 22–23. That would be autumnal equinox in the northern hemisphere and vernal equinox in the southern hemisphere.