The name of the observance for September 11th is a proper noun. The official designation is Patriot Day. It is a national day of remembrance, not a federal holiday, which is a key distinction in its legal and civil status. Federal holidays typically involve the closure of non-essential federal government offices and paid time off for federal employees, whereas a day of observance does not carry these requirements.
Patriot Day was established by U.S. Presidential Proclamation 7461, signed by President George W. Bush on September 4, 2002, following a joint resolution approved by the U.S. Congress on December 18, 2001. The day is observed annually with specific protocols, including a call for a moment of silence at 8:46 a.m. (Eastern Daylight Time) to correspond with the time the first plane struck the North Tower of the World Trade Center. Additionally, the flag of the United States is to be flown at half-staff at all homes, on the White House, and on all U.S. government buildings and establishments, both at home and abroad.
In 2009, Congress passed the Edward M. Kennedy Serve America Act, which designated September 11 as a National Day of Service and Remembrance. This legislation encourages Americans to participate in community service and charitable activities as a tribute to the victims, survivors, and first responders. Therefore, while universally known as "9/11," its official title is "Patriot Day and National Day of Service and Remembrance," reflecting a dual purpose of solemn commemoration and constructive civic engagement.