Action

A general word for having a bet on a game. If you "have action" on a game, you have a bet riding on it. It carries no judgment about whether the price was any good, which is the thing that actually matters.

American odds

A price shown with a plus or minus sign, measured against $100. A minus number is how much you risk to win $100, so -110 risks $110 to win $100. A plus number is how much you win on $100, so +150 wins $150 on a $100 stake.

Arbitrage

Betting every side of a market at different places so you come out ahead no matter the result. It works when the best price on each side adds up to less than 100%. The gaps are tiny and quick to close, and sportsbooks limit anyone who keeps doing it, so it is a grind rather than easy money.

Bankroll

The money you set aside for betting, kept separate from money you need for anything else. Sizing bets as a small fixed slice of the bankroll is what lets an edge, if you have one, survive the natural swings of results.

Break-even

The chance a bet has to win just to leave you where you started, set entirely by the price. A bet at -110 has a break-even of 52.4%. It is the bar the bet must clear, not an estimate of how often it actually wins.

Chalk

Slang for the favorite, the side the market expects to win. "Betting chalk" means backing favorites. A favorite is not automatically a good bet, because its short price can hide a high break-even bar that the team has to clear.

Closing line

The last price before a game starts, after all the news and money have been absorbed. It is the best public guess at the true chance, which is why bettors measure their own prices against it rather than against who happened to win.

Closing line value (CLV)

The gap between the price you took and the price the same bet closed at. Regularly beating the close is the clearest public sign of skill, because it is settled the moment the game starts and does not depend on how any single game ended.

Cover

To win a bet against the spread. A favorite covers by winning by more than the spread; an underdog covers by losing by less than the spread, or by winning outright. A team can win the game without covering, and lose the game but still cover.

Dead heat

A rule for markets with more than one winner, common in props and futures. If several results tie, your stake is split across the winners, so a bet that technically won can pay less than the full odds first suggested.

Decimal odds

A price shown as a single number, like 1.91 or 2.50, equal to the total returned per $1 staked, stake included. A number above 2.00 is an underdog and below 2.00 is a favorite. One divided by the decimal price gives the break-even chance.

De-vig (no-vig)

Removing the sportsbook fee from a price to estimate the fair chance underneath. You shrink both sides of a market in proportion until they add up to exactly 100%. What is left is a fair estimate of each side's true chance.

Edge

An advantage that makes a bet worth more than it costs on average. In practice the only edge most bettors can get is a price better than the fair price, which usually means shopping for a number that beats where the game closes.

Even money

A price that pays exactly your stake in profit if it wins, shown as +100 in American odds or 2.00 in decimal. Risk $100 to win $100. It sits right between a favorite and an underdog and implies a break-even chance of 50%.

Expected value (EV)

What a bet is worth on average if you could make it many times over. You multiply the fair chance of winning by what you win, then subtract the chance of losing times what you lose. Positive EV pays over the long run; negative EV costs. It is an average, never a promise about one bet.

Favorite

The side the market expects to win, shown with a minus moneyline like -180. The shorter the price, the higher the break-even chance it carries, so even a strong favorite can be a poor bet if the price is too short.

Fractional odds

A price shown as a fraction, like 5/1 or 1/2, common outside the United States. The fraction is profit to stake: 5/1 wins $5 for every $1 risked, and 1/2 wins $1 for every $2 risked. Add 1 and you have the decimal price.

Futures

A bet on something that settles far ahead, like a team to win the championship or a season win total. Futures markets carry a very large fee spread across the whole field, and they lock your money up for months, so the big payout comes at a steep cost.

Handle

The total amount of money a sportsbook takes in bets over some period. It is an industry figure about volume, not a signal about any single bet, and it says nothing about whether a given price is fair.

Hedge

Betting the other side of something you already backed, to lock in a known result no matter what happens. Hedging trades the full swing for a smaller sure thing, and because the hedge is a fresh bet with its own fee, the certainty always costs a little.

Hold

The sportsbook's built-in margin on a market, the share it expects to keep once both sides are balanced. It is the overround seen from the book's side. A lower hold means a cheaper price for the bettor, which is why shopping matters.

Implied probability

The chance a price implies, found by turning the odds into a percentage. Because of the fee, the two sides of a market add up to more than 100%, and the amount over 100% is the fee, not a real chance.

Juice

Everyday slang for the sportsbook fee built into every price, the same thing as the vig. "Reduced juice" means a smaller fee, which is a genuine selling point because the fee is the biggest cost in betting you can actually control.

Limit

The most a sportsbook will let you bet on a given market, and also what the book does to winning bettors when it cuts their maximum stake to almost nothing. Getting limited is the common fate of bettors who keep beating the closing price.

Line

The number a sportsbook posts for a bet: the spread, the total, or the moneyline price. Lines move before a game as news and money arrive, so the line you take early can differ from the one at kickoff.

Line shopping

Checking the same bet at several places and taking the best price. It is the simplest edge in betting, because it improves the price without changing the pick, and over a season the difference adds up to real money.

Live betting

Betting on a game while it is happening, with the price updating play by play. The fee is usually wider live than before the game, and the speed favors the sportsbook, so the bar a live price has to clear is higher, not lower.

Middle

Holding both sides of a game at different numbers, so a result that lands in the gap wins both bets at once. A middle usually costs a small fee when it misses and occasionally pays double, and only the numbers say whether the trade is worth it.

Moneyline

A bet on which team wins the game outright, with no spread. The favorite pays less than your stake and the underdog pays more. A short favorite price hides a high break-even bar, so a moneyline is judged by the chance it needs against a fair estimate.

Overround

The amount by which both sides of a market add up to more than 100%. It is the technical name for the fee seen in the prices. On a true coin-flip game priced -110 each way, the two sides total 104.8%, so the overround is 4.8 points.

Over / under

A bet on the total combined score of both teams against a posted number. The over cashes if the real total is higher, the under if it is lower. Who wins the game does not matter, only the sum.

Parlay

A single bet that ties several picks together, where every leg has to win. The payout multiplies, which is the draw, but the fee is charged on each leg and stacks, so a parlay costs more per dollar than the single bets that make it up.

Pick ’em

A game with no favorite on the spread, where neither side gets a head start, listed as "PK" or a spread of zero. The bet becomes simply who wins, priced close to even money on each side before the fee.

Pleaser

The mirror image of a teaser: you move the line against yourself across several legs in exchange for a much bigger payout. Moving the line the wrong way makes each leg less likely, and the stacked fee makes a pleaser one of the most expensive bets on the board.

Prop

Short for proposition bet, usually a bet on one player's number, like passing yards or points, over or under a posted line. Props tend to carry a higher fee than game lines and the line moves between places, so the bar is higher and shopping matters more.

Puck line

Hockey's version of the spread, almost always fixed at 1.5 goals, with the price doing the balancing. A favorite at -1.5 must win by 2 or more, which is demanding in a one-goal sport, so it often pays a plus price.

Push

When a result lands exactly on a whole-number line, so the bet neither wins nor loses and your stake is returned. Half-point lines like -3.5 exist to remove the push. Inside a parlay, a pushed leg simply drops out and the parlay recalculates.

Run line

Baseball's version of the spread, almost always fixed at 1.5 runs, with the price doing the work. Because one-run games are common, a favorite at -1.5 must win by 2 or more, so its run line often pays a plus price.

Same-game parlay

A parlay built from several legs of one game. The legs are usually linked, so multiplying their chances gives the wrong number. The true chance is hidden in how the sportsbook built the payout, which makes a same-game parlay hard to price by hand.

Sharp

A bettor who wins over the long run, usually by getting prices that beat the close rather than by picking more winners. The opposite is sometimes called a square. The label is about the quality of the prices taken, not a hot streak of results.

Spread

A head start in points given to the underdog to make the two sides a near coin flip. A favorite at -6.5 must win by 7 or more; the underdog at +6.5 can lose by 6 or fewer, or win. Both sides are usually priced near -110.

Steam

A fast, one-directional line move, when a price jumps as a wave of money hits the same side at once. It describes the speed and agreement of the move, not whether the move is right. Chasing steam usually means paying the new, worse price.

Teaser

A parlay where you move the spread or total in your favor across several legs, for a smaller payout. The extra points are not free: the payout drops and the fee is built into the drop, so the question is whether the points raise the real chance by more than they cost.

Total

The sportsbook's posted number for the combined score of both teams, bet as an over or an under. It ignores who wins. Low-scoring sports like hockey have small totals where a single goal matters; basketball totals run into the 200s.

Tout

Someone who sells sports picks. A tout's income comes from selling picks, which is not the same as profiting from betting them, so a tout can get rich while subscribers lose. Judge a tout by the prices their picks were given against the market, not by a hot streak.

Unit

A fixed slice of your bankroll that you treat as one normal bet, often about 1%. Betting in units keeps your stake steady so a cold streak cannot talk you into chasing. A tout's "unit" is whatever they say it is, so unit counts across people do not compare.

Variance

The natural swing of random results around their true average. Variance is loud over a few bets and quiet over many, which is why a hot streak proves little and it takes hundreds of bets to tell skill from luck.

Vig (vigorish)

The fee built into every price, also called juice. You never see it as a line item; you see it as odds a little worse than fair. It is the biggest cost in betting you can control, by shopping for a smaller one.