What does n-1 mean in biking?

Excuse me, could you please clarify for me the meaning of "n-1" in the context of biking? I'm a bit confused as to how it applies to cycling terminology or strategies. Is it related to the number of gears used, the number of riders in a group, or perhaps a specific training technique? I'd appreciate it if you could elaborate on this term and its significance in the world of biking.