What Is a Range, Really?
A range = the set of all hands the opponent can hold in the current spot, based on what they\'ve done so far. Example: an opponent who opens from UTG in a 6-max game typically has ~14% of hands: 77+, AJs+, KQs, AQo+.
The range isn\'t static — it narrows every time the opponent makes a new decision. A flop call removes weak hands that would fold. A turn bet narrows further. By the river, the range might be just 4-8 specific combos.