You can use D-day to refer to the day that is chosen for the beginning of an important activity.
D-day for my departure was set for 29th June.
N-UNCOUNT
You can use D-day to refer to the day that is chosen for the beginning of an important activity.
D-day for my departure was set for 29th June.
N-UNCOUNT
Collins COBUILD Advanced Learner's English Dictionary. Английский словарь Коллинз COBUILD для изучающих язык на продвинутом уровне. 2006