What does the abbreviation “V-J” mean in V-J Day, the 1945 celebration of Japan's defeat?

“V-J” means “Victory over Japan” in the name V-J Day.

The phrase describes the Allied victory over Japan at the end of World War II. In the United States, President Harry S. Truman proclaimed 2 September 1945 as V-J Day after Japan formally signed the surrender document aboard USS Missouri.

The term is sometimes used for celebrations on 14 or 15 August, when news of Japan's acceptance of the Allied terms reached different countries. The formal surrender ceremony, however, occurred on 2 September. This difference explains why historical references can associate V-J Day with more than one date.

The earlier V-E Day marked victory in Europe after Germany's surrender in May 1945. V-J Day therefore identifies the separate victory in the Pacific and Asian theaters, not the end of fighting in Europe.