Effective stack
The smaller of two players' stacks: the most either one can win from or lose to the other.
Example
You have 200 and they have 80, so the effective stack is 80.
Also written: effective stacks.
Related
Practise it in 5 minutes Stacks, a short free lesson.
Quads is for adults, 18 and over. It teaches with play chips only: there is no real money, ever.