The term "September 11th" functions as a proper noun. While it denotes a specific date on the calendar, its primary grammatical and cultural role is to name a singular, historically significant event: the terrorist attacks on the United States in 2001. This classification is critical because it elevates the phrase from a simple temporal marker to a designation with a fixed, profound meaning, similar to other event-based proper nouns like "the Fourth of July" or "D-Day."
In direct response to the embedded temporal query, the historical event designated by this proper noun occurred on a Tuesday. The date was September 11, 2001. It is important to distinguish this specific historical context from the general calendar date. As a recurring date, "September 11th" falls on a different day of the week each year according to the Gregorian calendar cycle. For instance, in 2024, the date falls on a Wednesday, and in 2025, it will fall on a Thursday.
The distinction between the proper noun and the simple date is therefore key to a complete understanding. The question "what day" can be interpreted in two ways: referencing the day of the week for the specific historical event, which is immutably a Tuesday, or referencing the day of the week for the current or a future year, which is variable. The cultural weight of the term, however, ensures that its primary association remains with the events of Tuesday, September 11, 2001.
