I was listening to Coffee Break French audio, season 4 episode 18. Near the beginning, the commentator says he has only a few days left until his holidays start. There is some phrase used like "je jis moins jours" or "j'ai J moins jours" (something like that). I would love to know what he is saying
He says C'est J moins 2, literally "it's D minus two" (only two days left before the vacations).
When English says 'the D-Day', we say le jour J1.
Note that jour J is not restricted to a military context. That might be any day when something special is going to happen, happens, or happened, like 'the big day'. We also use the similar heure H.
Voyons, réfléchissez... Vous m'avez bien dit que A a été tué par B à l'heure H du jour J en un point P ? Eh bien, mon chèque dit : payez à l'ordre de X la somme de Y millions, signé Z ! CQFD.
Pierre Dac, Signé Furax, La lumière qui éteint, 1958.
1 But while en English, D-Day was generic military jargon that was popularized after the 1944 Normandy landing and kept that single mainstream meaning for most native speakers, French can use le jour J for any event in whatever context. We might also use D-Day to refer to the same date although the usual term is le Débarquement.