The term "september 11 holidays" functions as a noun phrase. In this construction, "holidays" is the head noun, which is being modified by "September 11." The date "September 11" acts as a noun adjunct (or a compound adjective), specifying the particular holidays being referenced. Grammatically, the phrase refers to commemorative events or observances related to that specific date.
In the United States, September 11 is officially designated as Patriot Day and a National Day of Service and Remembrance. It is a national observance, not a federal holiday. This distinction is critical: a federal holiday typically entails the closure of government offices, banks, and schools, and is often associated with celebration or leisure. In contrast, an observance like Patriot Day is a day of solemn commemoration marked by specific rituals, such as flying flags at half-staff, holding memorial services, and observing moments of silence to honor the victims of the 2001 terrorist attacks.
Therefore, while the term is grammatically a valid noun phrase, its practical application is semantically inaccurate and generally considered inappropriate. The word "holiday" carries connotations of celebration that conflict with the somber and reflective nature of the day. For clarity, accuracy, and sensitivity, it is more appropriate to use terms such as "observance," "commemoration," "day of remembrance," or the official designation, "Patriot Day."
