noun, feminine/fɛ̃ də s(ə).mɛn fɔl/
Thanksgiving Weekend or Black Friday Weekend (the shopping period from Thanksgiving Thursday (U.S. Thanksgiving Day) through Cyber Monday (cyberlundi), including Black Friday (vendredi noir or vendredi fou), with large discounts in the prices of goods)
Literally, “crazy weekend”. From the expansion of vendredi fou (“Crazy Friday”) into a weekend.