Sports betting glossary

A three-outcome market: 1 (home win), X (draw), 2 (away win), generally over regulation time.

The reasoning and data (statistics, form, context) that lead to a prediction, before it's checked against the market.

When prices from several bookmakers on the same outcomes drift far enough apart that a position covering every outcome would, in theory, profit whatever the result.

also known as: surebet

A handicap that usually leaves a market with two sides. A .5 line rules out a refund. A quarter line splits the stake across two neighbouring lines and can pay a half-win or a half-loss.

Betting for an outcome to happen, like a standard bet placed with a bookmaker.

Money you set aside from your everyday budget for sports betting only, and track over time.

A tax on the stakes an operator receives. It's separate from any tax a player might owe on their own winnings.

A platform that matches opposing positions (back and lay) between participants instead of setting its own price. It usually charges a commission on net winnings.

The sum of implied probabilities across all outcomes of a market. It's 100% with no margin and climbs once a margin is built into the prices.

The excess built into a market's prices: the sum of implied probabilities across all outcomes, minus 100%.

A classification that crosses business model (sharp/soft) with price formation (market maker/follower). The betting exchange is a separate model.

Odds raised by the operator on one specific outcome and played with your own money, usually with a lower maximum stake.

also known as: price boost, odds boost

The "both teams to score" market. Yes if each side scores at least once, No if either side stays at 0.

A buyback offer the bookmaker prices on a bet you've already placed, before the event ends. It's the bookmaker's number, which sets it apart from an exit at market price.

The gap between the odds you took and the closing odds, as a percentage: odds taken ÷ closing odds − 1.

The last odds a bookmaker offers before kick-off. They're the reference for judging a price taken earlier.

The cut a betting exchange takes from the net profit of a winning bet. Factor it in whenever you compare with a bookmaker's price.

A market where you name the exact final score. Prices are usually high, given how many outcomes are possible.

A market with three selections (1X, 12, X2). Each one covers two of the three outcomes of a 1X2, so the price is lower than the matching 1X2 bet.

A bet on one team where a draw refunds your stake instead of losing it.

How far a bankroll has fallen from its latest peak, in absolute terms or as a percentage of that peak.

A whole-number handicap applied to the final score. It keeps three outcomes: handicap win, handicap draw and handicap loss.

The theoretical average result of a decision repeated many times: (estimated probability × odds − 1) × stake.

The odds that follow from a probability you've estimated independently of the market: 1 ÷ estimated probability.

A staking plan that keeps the same absolute amount on every bet, whatever the bankroll balance.

An operator that lines its odds up with one or more reference bookmakers rather than building them itself.

A fraction of the Kelly result (usually half or a quarter) staked instead of the full figure. It cuts your exposure to an error in the probability estimate.

Bet credit from a bookmaker that you can use to place a bet but not withdraw. If it wins, only the net profit is paid, never the stake.

Stakes collected minus winnings paid out to bettors. It's the regulatory measure of an operator's revenue, before costs and taxes.

An artificial adjustment to the score, margin or total, used to settle a market.

The total amount wagered by bettors with an operator over a given period.

The probability you can read off a decimal price: (1 ÷ odds) × 100, margin included.

A bet placed after kick-off, at a price recalculated continuously as the match unfolds.

A formula that turns odds and an estimated probability into the share of bankroll to commit. It maximises the geometric growth rate of a capital bet repeatedly, not the gain from a single bet.

Betting against an outcome. The layer keeps the backer's stake if the outcome doesn't happen, but pays the backer's winnings if it does.

The most a layer can lose if the outcome they bet against happens. It's the backer's stake multiplied by the odds minus 1.

The reference value in a totals or handicap market (the 2.5 in Over 2.5, the -1 in a handicap). A selection is compared against it at settlement.

The amount that can be matched at a given price, mainly on a betting exchange. A displayed price isn't always available for any stake size.

A betting category offered on an event (1X2, over/under, handicap…). It defines the possible outcomes and how they're settled.

A bookmaker that builds its own prices instead of copying other operators.

An odds movement that combines several notable features (intensity, speed, timing, consensus, consistency) without being a prediction.

The operator closing a market for a moment while an in-play event (a goal, a card, an injury) is worked into a new price. Usually a few seconds, then it reopens at the updated price.

A progression that doubles the stake after each loss to win it back on the next win. It raises exposure and never changes the expected value of the next bet.

The market on who wins the match, usually with two outcomes and no draw.

What an operator has left after costs, taxes and other expenses, once gross gaming revenue is worked out.

The odds you get once a market's overround is spread back across its outcomes, by proportional normalisation or an equivalent method.

The probability left after spreading a market's overround across its outcomes. It's an estimate, not the true probability of the outcome.

The price an operator shows for an outcome, in one of three usual formats: decimal, fractional or American.

Three ways to write the same price. Decimal gives the total return per 1 staked, fractional the net gain, American the gain per 100 staked (or the stake needed to win 100).

A totals market: you bet above (Over) or below (Under) a line, on a total of goals, points or games.

The part of the book percentage above 100%, which is the margin a bookmaker builds into a market's prices.

also known as: vig, vigorish

A statistical model that gives every possible match score a probability, starting from an expected average number of goals. It assumes goals are independent and the scoring rate is constant. Football only roughly meets both assumptions.

An argued opinion on how a match will end, separate from the analysis and data behind it.

The share of stakes an operator actually keeps once every bet is settled. Don't confuse it with the theoretical margin shown when the price is set.

A bet placed with your own money whose stake comes back if it loses, usually as a free bet rather than withdrawable cash.

also known as: money-back offer

The chance that a bankroll runs out before reaching a goal. It depends on starting capital, stake size and variance.

The observed return on settled bets: net profit ÷ total amount staked × 100.

How many decisions it takes before a betting record means anything. It depends on the odds played, the assumed edge and the variance.

Markets more specific than the main one: corners, cards, goalscorers, player stats, time-based markets, team totals.

The specific choice made on a market (Over, a team, an outcome). The market itself defines the set of possible choices.

Two informal types of bookmaker. Sharps run low margins and treat informed bets as a signal. Softs aim at the general public, with higher margins and promotions.

A fixed fraction of a bankroll used as the betting reference, so each bet stays in proportion to the capital at risk.

The rule that sets the size of the stake at each decision: a fixed amount, a share of the bankroll, or a progression tied to earlier results. It never says whether to bet.

A fast, visible odds movement that hits several bookmakers and spreads across the market.

The commercial name for a betting arbitrage gap. It's the same thing as "arbitrage", in the vocabulary of the sites that specialise in finding them.

The gap between an independently estimated probability and the one the offered odds would require. It's positive when the estimate beats that requirement.

also known as: edge

A sum of implied probabilities below 100% on a market. You can get there by combining the best odds from several bookmakers.

A bet whose estimated probability is higher than the offered odds require: edge = estimated probability × odds − 1.

The spread of observed results around a theoretical expectation. It gets wider when the odds played are high and the sample is small.

How many times a bonus (or bonus plus deposit) must be bet before it can be withdrawn. In Great Britain they've been capped at 10 times since 19 January 2026.

also known as: playthrough, rollover

An incentive for a new customer on sign-up, first deposit or first bet, as a free bet, bonus funds or a refund. It always comes with terms.

also known as: sign-up offer

A statistic that estimates, from the quality and position of the chances created, how many goals a team should have scored on average. An input for analysis, never a guaranteed outcome.