Full explanation — Stack
A stack is the full collection of chips a player currently controls at the table. In tournaments, stacks are usually measured in big blinds (BB) rather than raw chip counts, since blind levels rise over time: a "40BB stack" means the player has 40 times the current big blind. Stack size heavily influences strategy — short stacks favor push/fold decisions, while deep stacks allow more post-flop maneuvering, bluffing, and complex lines.