The standard three-week duration associated with many original-format attempts.
Where it comes from & how it’s used
Origin and show context
Survival language applied to Naked and Afraid. These skills and ordinary terms predate the program; first TV usage is not established here.
What it means now
Special episodes and spin-offs use other durations.
In a sentence
They planned supplies around a 21-day challenge.
Original example, not a contestant quote.