Pronunciation: (dē'dā"), [key]
1. Mil.the day, usually unspecified, set for the beginning of a planned attack.
2. June 6, 1944, the day of the invasion of western Europe by Allied forces in World War II.
3. Informal.any day of special significance, as one marking an important event or goal. Also,D-Day.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.