Glossary74 terms · free · no account

The betting glossary.

Every term defined plainly, in the number of sentences it actually takes — and each one linked to the calculator that does its arithmetic or the guide that explains it properly. Where a definition has a number in it, that number is computed rather than asserted.

Odds & Prices

American Oddsalso called Moneyline odds, US odds: Odds quoted against $100. A negative number is the amount you must risk to win $100 (−150 risks $150 to win $100); a positive number is what a $100 stake wins (+250 wins $250). Standard at US sportsbooks.Odds Converter→Guide →Decimal Odds Fractional Odds
Break-Even Win Rate: The win rate a bet needs to make exactly nothing. Numerically identical to the implied probability: 52.38% at −110, 58.33% at −140. It is the number any win rate should be judged against, never 50%.Break-Even Win Rate→Guide →Implied Probability ROI
Decimal Oddsalso called European odds: The total return per $1 staked, stake included. A $1 bet at 2.50 returns $2.50 — $1.50 profit plus the dollar back. Anything below 2.00 is a favourite. Standard in Europe, Canada, Australia and on every exchange.Odds Converter→Guide →American Odds Fractional Odds
Fractional Oddsalso called UK odds: Profit per unit staked, written as a fraction. 5/2 means five profit for every two risked, and the stake is excluded — so 5/2 and decimal 3.50 are the same price. Common in British horse racing.Odds Converter→Guide →Decimal Odds American Odds
Hold: The share of money staked a sportsbook keeps on a balanced market. A −110 / −110 market has a 4.76% overround but a 4.55% hold. Hold is the figure that describes the book’s actual take.Vig / Hold Calculator→Guide →Overround Vig
Implied Probability: The chance a price is quoting, found by dividing 1 by the decimal odds. −110 implies 52.38%. It is inflated by the sportsbook’s margin, so it is always higher than the market’s genuine estimate.Odds Converter→Guide →Break-Even Win Rate Vig No-Vig Odds
No-Vig Oddsalso called Fair odds, True odds: A market’s prices with the margin removed, found by scaling every implied probability down until they sum to 100%. A −120 favourite is really about 52.17%, not 54.55%. The benchmark every value calculation compares against.No-Vig Calculator→Guide →Vig Expected Value Closing Line
Odds Boostalso called Profit boost, Price boost: A promotion raising the profit portion of a price by a stated percentage. Only worth anything if the underlying price was competitive first — a padded −140 boosted 30% can still be worse than a −110 elsewhere.Odds Boost Calculator→Guide →Free Bet Bonus Bet
Overround: How far a market’s implied probabilities exceed 100%. Two −110 prices total 104.76%, so the overround is 4.76%. Not the same as hold, which divides that excess by the market total instead of by 1.Vig / Hold Calculator→Guide →Hold Vig
Reduced Juice: A sportsbook pricing standard markets tighter than −110, usually at −105. It cuts the break-even rate from 52.38% to 51.22%, which over a season is often the difference between a losing and a winning record.Guide →Vig Line Shopping
Vigalso called Vigorish, Juice, Margin, Cut: The sportsbook’s markup, built into the odds rather than charged as a fee. It is why a coin flip is priced −110 on both sides and why the two sides imply 104.76% between them.Vig / Hold Calculator→Guide →Overround Hold No-Vig Odds

Bet Types

Bonus Betalso called Stake not returned, SNR: Another name for a free bet where the stake is not returned. It can be converted to guaranteed cash by hedging: a $100 bonus at +200 hedged against −180 locks in $71.43.Bonus Bet Conversion→Guide →Free Bet Hedge
Free Bet: A promotional token that returns the profit but not the stake. A $100 free bet is worth about $48 used at −110 and about $80 used at +400, because you are buying profit per token — longer odds convert better.Free Bet Calculator→Guide →Bonus Bet Odds Boost
Futuresalso called Outright: A bet on a season-long outcome, such as a championship winner, settled months later. Futures markets carry the highest margin on the board — a full field can total well over 120% of implied probability.Futures Hedge Calculator→Overround Hedge
Moneylinealso called Match winner, Win bet: A bet on who wins outright, with no handicap involved. The favourite carries a negative price and the underdog a positive one, sized to reflect how one-sided the matchup is.Bet Payout Calculator→Point Spread American Odds
Parlayalso called Accumulator, Acca, Multi: Several bets combined into one, where every leg must win. The price is the legs multiplied, and so is the sportsbook’s margin — a six-leg parlay of −110 legs carries a 24.36% hold against 4.55% on a single bet.Parlay Calculator→Guide →Round Robin Teaser Same-Game Parlay
Point Spreadalso called Handicap, Line, Against the spread, ATS: A margin applied to the result so both sides price near even money. A −6.5 favourite must win by seven or more; the +6.5 underdog covers by losing by six or fewer, or winning.Moneyline Push Key Numbers
Prop Betalso called Proposition bet, Player prop: A bet on something other than the final result — a player’s yards, a team’s first score, a total number of strikeouts. Props carry noticeably higher margin than sides and totals, and lower limits.Vig Point Spread
Round Robin: A set of smaller parlays generated from a list of selections — every pair, every trio, and so on. It softens the all-or-nothing outcome of one large parlay without changing the expected value.Round Robin Calculator→Guide →Parlay
Same-Game Parlayalso called SGP: A parlay whose legs all come from one event. Because the legs are correlated, the price is set by a correlation model rather than by multiplying them — and the margin is typically higher than on an independent parlay.Guide →Parlay Correlation
Teaser: A parlay where you move every line in your favour — commonly six points in football — for a much shorter price. A two-team teaser at −110 needs each leg to win 72.37% of the time just to break even.Teaser Calculator→Guide →Parlay Key Numbers
Totalalso called Over/Under, O/U: A bet on the combined score of both teams rather than on who wins. You take the Over or the Under against a posted number.Point Spread Asian Total

Markets & Lines

Alternate Line: A spread or total offered away from the main number at a repriced cost — −9.5 instead of −3.5, at a longer price. Convenient, and consistently higher margin than the primary line it is derived from.Vig / Hold Calculator→Guide →Buying Points Point Spread Vig
Asian Handicap: A handicap that removes the draw, leaving two outcomes instead of three. Quarter lines like −0.25 split your stake across the two nearest half-lines, which is why a bet can settle as a half win or half loss.Asian Handicap Calculator→Guide →Asian Total Quarter Line Push
Asian Total: A total using quarter lines. Under 2.75 is half a bet at Under 2.5 and half at Under 3 — so exactly three goals is a half loss, returning half the stake, rather than a push or a full loss.Asian Totals Calculator→Guide →Asian Handicap Quarter Line
Backdoor Cover: A late, largely meaningless score that flips the spread after the result is settled — a garbage-time touchdown that turns a seven-point loss into a six-point one. It changes nothing about the game and everything about the bet.Guide →Cover Bad Beat Point Spread
Betting Exchange: A platform matching bettors against each other rather than against a house, charging commission on net winnings instead of building margin into the price. At 2% commission a 2.00 price is effectively 1.98, or −102.Exchange Commission→Guide →Lay Bet Vig
Buying Points: Paying extra juice to move a spread or total in your favour — taking +3.5 instead of +3 at a worse price. Worth it only when the half-point crosses a margin the sport actually produces often, and priced by the book on the assumption it usually is not.Odds Comparison→Guide →Key Numbers Point Spread Teaser
Cash Out: Settling a bet early for an amount the sportsbook calculates. It is a hedge the operator prices, with their margin applied on top of the margin already in the original bet — almost always worse than hedging yourself.Cash-Out Value→Guide →Hedge Vig
Closing Line: The final price before an event starts, after all information and money have arrived. In liquid markets it is the most accurate public forecast available, which is what makes beating it meaningful.Closing Line Value Calculator→Guide →Closing Line Value Steam No-Vig Odds
Closing Line Valuealso called CLV: How your price compares to the closing price. Taking +105 on a market that closes −105 is about 5% of CLV. It signals skill far faster than results — dozens of bets rather than thousands.Closing Line Value Calculator→Guide →Closing Line Sample Size
Coveralso called Covering the spread, ATS: Beating the point spread rather than merely winning. A −6.5 favourite covers by winning by seven or more; a +6.5 underdog covers by losing by six or fewer, or by winning outright.Guide →Point Spread Backdoor Cover Push
First-Half Betalso called Half-time bet, 1H: A spread, total or moneyline settled on part of the game rather than all of it. Priced as its own market with its own margin, so a first-half line is not simply half the full-game number.Vig / Hold Calculator→Guide →Point Spread Total Live Betting
Half Win / Half Loss: The settlement of one half of a quarter-line bet when the two halves disagree. A half win pays profit on half the stake and refunds the other half; a half loss forfeits half and refunds half.Asian Handicap Calculator→Guide →Quarter Line Push
Key Numbers: Margins that occur far more often than their neighbours — 3 and 7 in American football, for example. Buying a half-point across a key number is worth much more than across an ordinary one, though how much requires real historical data.Guide →Point Spread Teaser
Lay Bet: Betting that something will not happen — taking the role a sportsbook normally occupies. Available on exchanges, and the mechanism behind hedging a position you already hold.Hedge Calculator→Betting Exchange Hedge
Line Shopping: Taking the best available price across several sportsbooks on bets you were making anyway. At a true 52% win rate over 500 bets of $100, it is the difference between losing $364 at −110 and making $762 at −105.Odds Comparison→Guide →Reduced Juice Closing Line Value
Live Bettingalso called In-play betting: Betting a game while it is being played, with prices repriced continuously. Costs roughly twice a pregame line — around 8.33% hold at a typical −120 against 4.55% at −110 — because the book is charging for the risk of pricing in real time.Cash-Out Value→Guide →Cash Out Vig First-Half Bet
Middle: Betting both sides at different lines so that a result landing in the gap wins both. Outside that window one side wins and one loses, costing the margin on both — it is a bet on a specific margin, not free money.Middle Calculator→Guide →Arbitrage Hedge
Pushalso called Tie, Void: A bet that lands exactly on the line and is refunded. Pushes are not wins or losses and should be excluded from a win rate — but they do change a bet’s value, because the money is only at risk when a push does not occur.Push-Adjusted EV→Guide →Half Win / Half Loss Point Spread
Quarter Linealso called Split line: An Asian line ending in .25 or .75, which is really two bets of half your stake on the neighbouring half-lines. −0.75 is half at −0.5 and half at −1.Asian Handicap Calculator→Guide →Asian Handicap Half Win / Half Loss
Reverse Line Movementalso called RLM: A line moving against the side taking most of the bets — the public is on one team and the number drifts toward the other. Usually read as respected money outweighing volume, though a book managing its own exposure produces the same picture.Guide →Steam Sharp Closing Line
Steamalso called Steam move: A fast, coordinated line move across many sportsbooks at once, usually driven by respected money. Chasing steam after the move has happened generally means betting a worse number than the one that caused it.Closing Line Sharp

Math & Analytics

Arbitragealso called Arb, Sure bet: Backing every outcome across books at prices summing to less than 100% implied probability, guaranteeing profit. A +110 / +105 pair totals 96.4% and returns 3.73% of the stake regardless of the result.Arbitrage Calculator→Guide →Hedge Dutching Middle
Bankroll: Money set aside for betting, separate from everything else, and sized so losing all of it changes nothing. Its purpose is to let you keep staking the same amount through a losing run.Bankroll / Unit Calculator→Guide →Unit Risk of Ruin Drawdown
Confidence Interval: The range of true win rates consistent with what you observed. A 55-45 record has a 95% interval of about 45% to 64% — wide enough to include losing badly, which is why small records prove nothing.Win Rate Confidence→Guide →Sample Size Variance
Correlation: When one outcome makes another more or less likely. Correlated legs cannot be priced by multiplication, which is why same-game parlays use a correlation model and why several bets on one game are really one larger bet.Guide →Same-Game Parlay Parlay
Drawdown: The distance from a bankroll peak to the trough that follows. A break-even bettor at −110 hits a five-loss run about 74% of the time within 100 bets, so deep drawdowns are routine rather than diagnostic.Maximum Drawdown→Guide →Variance Risk of Ruin
Dutching: Splitting a stake across several outcomes in one market so any of them returns the same amount. Unlike arbitrage it is not automatically profitable — it converts several opinions into one position at a known return.Dutching Calculator→Guide →Arbitrage Hedge
Edge: Your probability estimate minus the break-even rate the price demands, in percentage points. A 55% estimate against −110 is a 2.62-point edge — small, and enough, if it is real.Betting Edge Calculator→Guide →Expected Value Break-Even Win Rate
Expected Valuealso called EV, +EV, Plus EV: What a bet is worth on average across every time you could make it. At −110 with a genuine 55% estimate it is +$5.00 per $100 staked. It says nothing about whether this particular bet wins.Expected Value (EV) Calculator→Guide →Edge Break-Even Win Rate No-Vig Odds
Flat Betting: Staking the same amount on every bet regardless of confidence. It is the correct default, because varying stakes by confidence only helps if confidence tracks being right — and it keeps your own record readable.Bankroll / Unit Calculator→Guide →Unit Kelly Criterion
Hedge: Backing the opposite side of a bet you already hold to guarantee an outcome. It reduces the best case to eliminate the worst, and it almost always costs expected value — you pay margin a second time.Hedge Calculator→Guide →Arbitrage Cash Out Lay Bet
Kelly Criterion: The stake that maximises long-run bankroll growth: f = (b × p − q) ÷ b. At −110 with a 55% estimate it recommends 5.5% of bankroll — aggressive enough that most people bet a quarter or half of it.Kelly Criterion Calculator→Guide →Bankroll Unit Risk of Ruin
Regression to the Mean: The tendency of extreme results to be followed by ordinary ones. A hot streak is usually variance rather than a change in skill, and it will end without anything having gone wrong.Streak Probability→Guide →Variance Sample Size
Risk of Ruin: The probability a losing run empties the bankroll before an edge compounds it. It rises far faster than linearly with bet size, which is why 5% units are a different category of outcome from 1%, not merely five times bolder.Risk of Ruin→Guide →Bankroll Drawdown Variance
ROIalso called Return on investment, Yield: Profit divided by total staked. Watch the denominator: $2,500 from 500 bets of $100 is 5% on turnover and 50% on a $5,000 bankroll, and only the first is what ROI normally means.Betting ROI Calculator→Guide →Unit Break-Even Win Rate
Sample Size: How many bets it takes for a result to mean something. Separating a 55% win rate from break-even at −110 takes about 5,689 bets — roughly eleven years at ten bets a week.Sample Size Calculator→Guide →Variance Confidence Interval Closing Line Value
Unit: One standard bet, expressed as a percentage of bankroll rather than a dollar figure — commonly 1%. Units make records comparable between bettors with different bankrolls.Profit / Units Calculator→Guide →Bankroll Flat Betting ROI
Variance: The spread of results around the expectation. In betting it dwarfs the signal: a real three-point edge is far smaller than the swing between one run of a hundred bets and the next.Bankroll Simulator→Guide →Sample Size Drawdown Regression to the Mean

Industry & Slang

"Lock": A bet claimed to be certain. No such thing exists. Every outcome can lose, and anyone selling picks with this word is telling you something about themselves rather than about the game.Guide →Expected Value Variance
Bad Beat: A bet lost to a late, improbable turn of events — a meaningless score changing a cover after the result is settled. Common, memorable, and not evidence of anything.Variance Key Numbers
Capperalso called Sports capper, Handicapper: Short for handicapper — someone who analyses games and publishes picks, usually for a fee. The word carries no qualification behind it: anyone can call themselves one, so the only thing that separates them is a complete, dated, published record including the losses.Win Rate Confidence→Guide →Handicapper Tout Sample Size
Chalk: The favourite, especially a heavy one. "Chalky" describes a slate where the favourites all won, or a bettor who habitually backs them.Square Moneyline
Chasing: Raising stakes to recover losses. It is the most reliable way to turn a survivable drawdown into a terminal one, because the bets have no memory of what you lost yesterday.Guide →Bankroll Drawdown Risk of Ruin
Expert Picksalso called Premium picks, Paid picks: Picks sold or published as coming from someone with an edge. The label is marketing, not a credential — nothing about it implies a tracked record. Ask for the bet count and the prices before treating any of it as expert.Guide →Capper Tout Sample Size
Free Picks: Picks published at no charge, usually as a sample of a paid service. Useful when they are graded publicly alongside the paid ones; misleading when only the winners resurface. The question is not whether they are free but whether they are counted.Guide →Capper Tout
Handicapperalso called Sports handicapper, Capper: Someone who assesses the relative strength of two sides and prices the difference — historically the person who set the handicap, now generally anyone selling picks. Judge one the way you would judge any forecaster: how many graded bets, at what prices, and were the losers published at the time.Sample Size Calculator→Guide →Capper Tout Confidence Interval
Handle: The total amount wagered on a market, event or over a period. Not the same as revenue: a book’s revenue is the handle multiplied by its hold.Hold ROI
Limit: The maximum a sportsbook will accept on a market. Limits are highest on major sides and totals and lowest on props — and are cut on individual accounts the operator would rather not take money from.Sharp Line Shopping
Off the Boardalso called OTB, Circled game: A market a sportsbook has pulled or heavily limited, usually because of an injury it cannot price yet. A circled game is the softer version: still available, at reduced limits. Both mean the book has told you it is unsure.Limit Steam
Sharpalso called Wiseguy, Sharp money: A bettor whose action sportsbooks respect, and by extension the money they move. A "sharp book" is one that takes such action and prices accordingly, which makes its lines a useful reference.Square Steam Closing Line
Squarealso called Public money: Recreational betting action, which skews toward favourites, overs and popular teams. Sportsbooks shade prices toward those preferences because that is where the volume is.Sharp Vig
Tout: Someone who sells betting picks. The useful questions are always the same: how many bets, at what prices, and were the losses published at the time or assembled afterwards.Guide →Sample Size Confidence Interval ROI

Educational content for informational purposes only. Nothing here is betting advice. 21+ (18+ where applicable).