Veterans Day, celebrated on November 11th, honors military veterans who have served in the United States Armed Forces. Veteran's day is a day to "honor America’s veterans for their patriotism, love of country, and willingness to serve and sacrifice for the common good."
At 11:00 A.M. on November 11, 1918, World War I, often called the "War to End All Wars," concluded with the signing of the armistice at Rethondes, France. One year later, November 11 was designated as Armistice Day in the United States to honor the sacrifices of those who served during the war. After World War II, Americans continued observing Armistice Day on November 11 and in 1954, the day was renamed Veterans Day to honor all American veterans.
Source: History of Veteran's Day - U.S. Department of Veterans Affairs