Patriot Day is indeed a real, federally recognized observance in the United States, established to commemorate the lives lost during the September 11, 2001, terrorist attacks. It is designated to be observed annually on September 11th. While it holds official recognition through federal legislation, its nature differs significantly from a traditional federal public holiday, such as Thanksgiving or Christmas.
Legally, Patriot Day was established by a joint resolution of the U.S. Congress (H.J. Res. 71) and signed into law by President George W. Bush on December 18, 2001, as Public Law 107-89. This legislation codified September 11th as "Patriot Day" and requested that the President issue a proclamation calling upon the people of the United States to observe the day with appropriate ceremonies and activities, including moments of silence. Crucially, it is classified as a national day of remembrance and prayer, rather than a federal holiday on which government offices and many private businesses are closed. Observances typically include the display of the American flag at half-staff at government buildings and residences, and a moment of silence observed at 8:46 a.m. Eastern Daylight Time, marking the time the first plane struck the North Tower of the World Trade Center.
Therefore, while Patriot Day is a legitimate and officially sanctioned day of national commemoration, its "holiday" status is distinct. It serves as a solemn day of remembrance and reflection, encouraging public observance and respect for those who perished, rather than a day of rest from work or school. The term "real holiday" can be nuanced, but in the context of official recognition and national observance, Patriot Day unequivocally fits the definition, albeit with specific characteristics that differentiate it from a federal public holiday.