a month in the Gregorian calendar

the solar calendar now in general use, introduced by Gregory XIII in 1582 to correct an error in the Julian calendar by suppressing 10 days, making Oct 5 be called Oct 15, and providing that only centenary years divisible by 400 should be leap years; it was adopted by Great Britain and the American colonies in 1752

honoring the archangel Michael; a quarter day in England, Wales, and Ireland

first Monday in September in the United States and Canada

celebrated in the United States

US: the 4th Friday in September

the solar calendar now in general use, introduced by Gregory XIII in 1582 to correct an error in the Julian calendar by suppressing 10 days, making Oct 5 be called Oct 15, and providing that only centenary years divisible by 400 should be leap years; it was adopted by Great Britain and the American colonies in 1752

honoring the archangel Michael; a quarter day in England, Wales, and Ireland

first Monday in September in the United States and Canada

celebrated in the United States

US: the 4th Friday in September