Also known as: D-Day, Dデイ, オーヴァーロード作戦
Technically a military designation of the date a given operation commences, "D-Day" has come to be known as an alternate name for Operation Neptune on 6 June 1944, the date Allied forces (US, UK, Canada and Free French) launched the invasion of the French region of Normandy, code-named Operation Overlord, in World War II.