1. Back to School: This is the most common meaning. It refers to the start of the school year in France, typically in early September. It's a big event, marked by special back-to-school sales, new school supplies, and often a sense of excitement and anticipation.
2. Return from Vacation: In a more general sense, "la rentrée" can also refer to the return from a vacation or break, especially when it involves going back to work or daily routines. It's a period of readjustment and re-entering normal life after a time of relaxation.
So, when you hear "la rentrée", it's usually referring to the start of the school year, but it can also encompass the general idea of returning to a routine after a break.