Expression: À la rentrée !
Pronunciation: [a la ra(n) tray]
Meaning: See you in September! See you this fall!
Literal translation: at the return
Notes: In August, major sectors of France slow down or close up shop completely. School is out, the government is more or less AWOL, and many restaurants and other businesses are closed as well. Therefore, many French people are on vacation for all or part of the month, which means that la rentrée, in September, is more than just students and teachers going back to school; it's also everyone else returning home and going back to work, returning to normalcy.
À la rentrée ! is a valediction, similar to bonnes vacances ! (have a nice vacation), a way of saying good-bye and an acknowledgement that you'll see the other person when you both re-enter the real world after your prolonged vacation.
You can also use à la rentrée as a reference to that point in time, to explain when something will happen, as in Je vais acheter une nouvelle voiture à la rentrée - I'm going to buy a new car in early September / when school starts back up / after I get back from vacation.
Related expression: les affaires de la rentrée - back-to-school deals/sales
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