D-Day (born D-Day) – U.S. military designation of the day the operation began. Best-known “D Day” was June 6, 1944 – D-day landings of Allied troops on troops in Normandy (France) during the Second World War. D-Day is a term often used in military parlance to denote the day on which a combat attack or operation is to be initiated. “D-Day” often represents a variable, designating the day upon which some significant event will occur or has occurred; see Military designation of days and hours for similar terms. The initial D in D-Day has had various meanings in the past, while more recently it has obtained the connotation of “Day” itself, thereby creating the phrase “Day-Day”, or “Day of Days”. On the same principle, the equivalent terms in French, Basque, Romanian and Slovenian are Jour J, E eguna, Ziua-Z, and Dan D. The Normandy Landings were the landing operations of the Allied invasion of Normandy, also known as Operation Neptune and Operation Overlord, during World War II. The landings commenced on Tuesday, 6 June 1944 (D-Day), beginning at 6:30 AM British Double Summer Time (UTC+2). In planning, D-Day was the term used for the day of actual landing, which was dependent on final approval.