Veterans Day is an official United States public holiday, observed annually on November 11, that honors military veterans; that is, persons who served in the United States Armed Forces. It coincides with other holidays, including Armistice Day and Remembrance Day, celebrated in other countries that mark the anniversary of the end of World War I; major hostilities of World War I were formally ended at the 11th hour of the 11th day of the 11th month of 1918, when the Armistice with Germany went into effect. The United States previously observed Armistice Day. The U.S. holiday was renamed Veterans Day in 1954.

Veterans Day is not to be confused with Memorial Day, a U.S. public holiday in May; Veterans Day celebrates the service of all U.S. military veterans, while Memorial Day honors those who died while in military service.[1] It is also not to be confused with Armed Forces Day, a minor U.S. remembrance that also occurs in May, which specifically honors those currently serving in the U.S. military.
On November 11, 1919, U.S. President Woodrow Wilson issued a message to his countrymen on the first Armistice Day, in which he expressed what he felt the day meant to Americans:

ADDRESS TO FELLOW-COUNTRYMEN
The White House, November 11, 1919.

A year ago today our enemies laid down their arms in accordance with an armistice which rendered them impotent to renew hostilities, and gave to the world an assured opportunity to reconstruct its
Taken from Wikipedia