Veterans Day (originally known as Armistice Day) is a federal holiday in the United States observed annually on November 11, for honoring military veterans, that is, persons who have served in the United States Armed Forces (and were discharged under conditions other than dishonorable). It coincides with other holidays including Armistice Day and Remembrance Day which are 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. At the urging of major U.S. veteran organizations, Armistice Day was renamed Veterans Day in 1954.

Veterans Day is distinct from 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 had died while in military service. Another military holiday that also occurs in May, Armed Forces Day, honors those currently serving in the U.S. military. Additionally, Women Veterans Day is recognized by a growing number of U.S. states that specifically honors women who have served 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:

The United States Congress adopted a resolution on June 4, 1926, requesting that President Calvin Coolidge issue annual proclamations calling for the observance of November 11 with appropriate ceremonies. A Congressional Act (52 Stat. 351; 5 U.S. Code, Sec. 87a) approved May 13, 1938, made November 11 in each year a legal holiday: "a day to be dedicated to the cause of world peace and to be thereafter celebrated and known as 'Armistice Day'."

 

Although originally scheduled for celebration on November 11 of every year, starting in 1971 in accordance with the Uniform Monday Holiday Act, Veterans Day was moved to the fourth Monday of October (October 25, 1971; October 23, 1972; October 22, 1973; October 28, 1974; October 27, 1975; October 25, 1976, and October 24, 1977). In 1978, it was moved back to its original celebration on November 11. While the legal holiday remains on November 11, if that date happens to be on a Saturday or Sunday, then organizations that formally observe the holiday will normally be closed on the adjacent Friday or Monday, respectively.

According to Wikipedia