The term functions as a proper noun. It operates as a single, cohesive unit to name a specific, major historical event. While composed of a numeral ("11"), an abbreviated month ("sep"), and an abbreviated location ("ny"), its grammatical role is to act as a unique identifier, similar to other event-based proper nouns like "D-Day" or "Y2K."
This specific designator refers to the series of coordinated terrorist attacks by al-Qaeda against the United States on the morning of September 11, 2001. The "ny" component specifically localizes the reference to the events in New York City, where two hijacked commercial airliners were crashed into the North and South Towers of the World Trade Center complex, leading to their eventual collapse. The phrase encapsulates the date, event, and primary location in a highly condensed format.
In practical application, this shorthand is most often used in digital contexts such as search engine queries, data tagging, or social media hashtags where character limits and efficiency are paramount. Its use presupposes a shared base of cultural and historical knowledge, allowing for the communication of a complex and significant event with minimal characters. The phrase serves as a direct and unambiguous pointer to the 2001 attacks for any audience familiar with the event.
