In V-J Day, what does the abbreviation V-J mean?

V-J in V-J Day means Victory over Japan.

The abbreviation identifies the Allied victory over Japan in the Pacific War, which ended World War II. It parallels V-E Day, meaning Victory in Europe, which marked Nazi Germany’s surrender in May 1945.

The term can refer to more than one date because news of Japan’s acceptance of surrender terms traveled across time zones. The United States commonly observes August 14, 1945, while many British Commonwealth countries use August 15. Japan’s formal surrender ceremony took place later, on September 2, aboard USS Missouri in Tokyo Bay.

V-J Day is therefore a victory designation, not the name of the surrender document. That document was the Japanese Instrument of Surrender, which formally ended hostilities.