Expression: le jour J
Pronunciation: [leu zhoor zhee]
Meaning: D-Day, the big day
Literal translation: J day
Register: normal
Notes: The French expression le jour J literally refers to D-Day, 6 June 1944, when the Allies invaded Normandy, France during World War II. More generally, both le jour J and D-Day can refer to the day any military operation will occur. The J stands for nothing more exciting than jour.
Beyond the military, le jour J is used figuratively for the date of an important event, such as a wedding, graduation, or contest; it is equivalent to "the big day" in English. (While D-Day can also be used figuratively, it is much less common and is limited to less than joyous occasions, such as deadlines and visiting your in-laws.)
Examples
Samedi, c'est le jour J.
Saturday is the big day.
Le jour J approche !
The big day is almost here!
Synonym: le grand jour
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