By a joint resolution of the U.S. Congress on Dec. 18, 2001, September 11 was designated as Patriot Day. The resolution calls for the president of the United States to issue a yearly proclamation requesting that all U.S. flags be flown at half-staff.
Further, Americans are asked to honor the dead with a moment of silence beginning at 8:46 AM, Eastern Standard Time, the time that the first airplane struck the World Trade Center, and to respect the ceremonies of remembrance when they are conducted.
Prior to passage of the resolution, several other names had been proposed for the day, such as the National Day of Remembrance and the National Day of Prayer and Remembrance.
Reference: http://www.history.com/topics/patriot-day
