The keyword phrase "September 11th" functions grammatically as a proper noun. While it represents a specific calendar date, its usage in this context refers to the series of terrorist attacks that occurred in the United States in 2001. As a proper noun, it serves as the unique name for that historical event. In the United States, this date is officially known as Patriot Day and is also widely referred to by the numerical shorthand 9/11.
The official designation, Patriot Day, was established by a proclamation by President George W. Bush on December 18, 2001 (U.S. Public Law 107-89). It is observed annually as a national day of remembrance, with the U.S. flag flown at half-staff and a moment of silence to honor the nearly 3,000 victims. The term 9/11 (pronounced "nine-eleven") is the most common colloquialism, derived from the American date format (month/day), and is used globally in media and public discourse to refer to the attacks. In 2009, federal law also designated the date as a National Day of Service and Remembrance, encouraging Americans to engage in charitable service as a tribute.
The existence of multiple names reflects the event's complex legacy. The term "September 11th" itself has been lexicalized, transforming from a simple date into a noun representing a pivotal moment in modern history. The formal title "Patriot Day" frames the commemoration within an official, national context of solemn remembrance. In contrast, designating it a "National Day of Service and Remembrance" provides a practical application for commemoration, channeling grief into constructive civic action and community engagement.
