What was the code name of the D-day invasion of Normandy?

Operation Overlord. the entire Battle sequence is, however popularitly referred to from it"s target date of D-Day- June 6, l944. D-day- the day the battle was initiated. then you had D plus One, etc in the chronicles as the larger Breakout campaign expanded- such target areas as St. Mere Eglise ( which tragically, means Holy Mother Church!) St. Vith, etc.