From MilitaryBenefits.info:
Veterans Day: The Veterans Day Moment of Silence calls on all Americans to observe two minutes of silence on Veterans Day, beginning at 3:11 pm Atlantic standard time, in honor of the service and sacrifice of veterans throughout the history of the nation. The 3:11 pm time was chose because in 1918, on the 11th hour of the 11th day of the 11th month, an armistice, or temporary cessation of hostilities, was declared between the Allied nations and Germany in World War I.
https://militarybenefits.info/veterans-vs-memorial-day/