Grammatically, "11 September" functions as a proper noun. While it denotes a specific calendar date, its primary use in contemporary discourse is as the formal name for the series of four coordinated terrorist attacks by the Islamic extremist group al-Qaeda against the United States on the morning of September 11, 2001. The term has become a specific signifier for this historical event, much like "Pearl Harbor" refers to the attack of December 7, 1941, rather than just the location itself.
The events encompassed by this proper noun involved the hijacking of four commercial airliners. American Airlines Flight 11 and United Airlines Flight 175 were crashed into the North and South Towers, respectively, of the World Trade Center complex in New York City, leading to their eventual collapse. A third plane, American Airlines Flight 77, was crashed into the Pentagon in Arlington, Virginia. The fourth plane, United Airlines Flight 93, crashed into a field in Shanksville, Pennsylvania, after its passengers and crew attempted to regain control from the hijackers. The attacks resulted in 2,977 fatalities, making it the single deadliest terrorist attack in human history.
The significance of "11 September" as a term extends beyond the immediate events to represent a watershed moment in modern history. It serves as a historical marker for the beginning of the "War on Terror" and precipitated major shifts in U.S. foreign policy, including the invasions of Afghanistan and Iraq. Domestically, it led to the creation of the Department of Homeland Security and the passage of extensive national security legislation, such as the USA PATRIOT Act. The term, therefore, encapsulates not only the attacks themselves but also their profound and lasting geopolitical, social, and cultural consequences.
