mathematics
Redraw
A redraw is a made hand that can still improve to an even better hand. For example, a set of queens with a draw to a flush has a redraw to a flush.
Removal
Removal, also known as blockers, is the effect of holding a card that reduces the number of combinations of certain hands that your opponent can have. If you hold the ace of spades, your opponent cannot have the nut spade flush on a board with three spades.
Reverse Implied Odds
Reverse implied odds are the chips you may lose on later streets when you make a hand that is good but not the best. They are the opposite of implied odds, and they make a call less attractive than the pot odds show.
ROI
ROI, return on investment, is a measure of profit in tournaments. It is calculated as a percentage by dividing the profit by the total buy-ins. For example, a profit of $500 on $5,000 in buy-ins is an ROI of 10 percent.
Solver
A solver is a program that calculates the best strategy for a given poker situation. You give it the stacks, bet sizes and ranges, and it gives a solution that is close to game theory optimal play.
Solver Solution
A solver solution is the strategy that a solver gives for a situation you entered: what to do with each hand and how often. It shows the expected value of each action.
Stack-to-Pot Ratio (SPR)
Stack-to-pot ratio, or SPR, is the ratio of the effective stack to the size of the pot. It tells you how many pots are left to bet, and strongly affects strategy.
Underdog
An underdog is a hand or player with a lower chance to win than the opponent. If your hand wins 20 percent of the time against another, you are the underdog and the other is the favorite.
Uphill
To go uphill is to chase a better hand, trying to outdraw it. A player who is uphill is behind and needs a card to win.
Variance
Variance is the natural up-and-down movement of your results around the average you expect over time. Even a winning player has losing days, weeks and months, because the cards are random.
Worst of It
The worst of it means fighting the odds: being in a situation where your wager has an unfavorable return. The opposite is the best of it. People say 'take the worst of it' or 'have the worst of it'.