Range
The set of hands played in a given situation
Definition
A range is the set of all hands a player can have in a given situation. Rather than thinking hand by hand in isolation, a solid player thinks in terms of ranges: "In this spot, I play 35% of hands — which ones?". It's one of the fundamental concepts of modern poker. Every preflop action (open, call, 3-bet, fold) corresponds to a precise range depending on position. Postflop, the range evolves on every street based on the actions taken. Ranges are shown on a 13×13 grid that lists every possible combination in Texas Hold'em. Mastering your ranges means knowing which hands to play in each situation without hesitation. That's exactly what spaced repetition enables: hardwiring the right decisions automatically. A well-built range is consistent, balanced and hard for opponents to exploit.
The BTN opening range in 6-max Cash Game at 100bb includes around 45% of hands: all pairs, broadway aces, suited connectors and many offsuit broadways. UTG, by contrast, opens only ~15% of hands because playing from early position is a major disadvantage.