Betting glossary
The essential vocabulary of sports betting, explained in one or two sentences each. Tap any term for a quick definition and where to go next.
Basics
Bad Beat
A bet that looked like a sure winner until a late, improbable swing flipped the result — a backdoor cover or a meaningless garbage-time score.
Bankroll
The dedicated pool of money you set aside for betting, separate from everyday finances. Managing it carefully is the single biggest factor in surviving variance.
Book / Bookie
Short for bookmaker: the person or company that sets the odds, takes the bets, and pays out winners. Their edge comes from the vig baked into every line.
Chalk
Betting slang for the favorite in a game or event. ‘Taking the chalk’ means backing the side the odds — and most of the public — expect to win.
Closing Line
The final line a market shows just before the event begins, after all the money and news have moved it. It is the market’s sharpest, most accurate price.
Cover
To beat the point spread: a favorite covers by winning by more than the number, an underdog by losing by less than it — or winning outright.
Line
The current odds, point spread, or total a sportsbook is offering on a market. Lines move as money comes in and as new information arrives.
Odds
A numerical expression of how likely an outcome is and how much a winning bet pays. American, decimal, and fractional are the three main formats.
Off the Board (OTB)
A game a sportsbook has temporarily refused to take bets on, usually because of an unconfirmed injury or other uncertainty. The market reopens once the news clears.
Opening Line
The first line a sportsbook posts for a market, before betting action and new information start to move it. Sharps often attack it for soft early numbers.
Push
A tie against the spread or total, where the result lands exactly on the number. No one wins, and every stake is refunded.
Sharp
A professional or highly skilled bettor who wins long-term by finding value, and whose action books respect enough to move their lines.
Square
A casual, recreational bettor who tends to back favorites and popular teams — the opposite of a sharp, and the side books lean on to balance their action.
Underdog (Dog)
The team or player the oddsmakers expect to lose, offered at plus-money odds so a winning bet pays more than it risks. Often shortened to “dog.”
Vig (Juice)
The bookmaker's built-in commission, baked into the odds on both sides of a market. It is why the implied probabilities of a market add up to more than 100%.
Odds & Probability
American Odds
Odds shown as a positive or negative number relative to $100 — +150 means a $100 bet wins $150, while -150 means you risk $150 to win $100.
Decimal Odds
Odds shown as the total return per $1 staked, including your stake — decimal 2.50 means a $1 bet returns $2.50. Common in Europe and on betting exchanges.
Dime Line
A market with only a 10-cent gap between the two sides’ prices — for example -120 / +110 — meaning a low 20-cent vig. Common in baseball moneylines.
Even Money
Odds that pay exactly your stake in profit — +100 in American, 2.00 in decimal. A winning $100 bet returns $100 plus your original stake.
Hook
The half-point tacked onto a spread or total, like the .5 in -7.5. It exists to prevent pushes by guaranteeing a game can’t land exactly on the number.
Implied Probability
The chance of an outcome implied by its odds, expressed as a percentage. Comparing it against your own estimate is how you spot a value bet.
Reduced Juice
A promotion where a book lowers its standard vig — say -105 instead of the usual -110 — so you risk less to win the same amount. It directly improves your long-run returns.
True Odds
The odds that reflect an outcome’s real probability, with no bookmaker margin added. Comparing them to the posted price reveals how much vig you are paying.
Bet Types
Against the Spread (ATS)
Betting a team to cover the point spread rather than just win the game. A team’s ATS record tracks how often it beats the number, not the scoreboard.
Draw No Bet
A soccer wager that removes the tie: pick a team to win, and if the match ends level your stake is simply refunded. It trades a lower payout for added safety.
Each Way
A two-in-one bet, half on a selection to win and half on it to ‘place’ by finishing in the top few. Common in horse racing and golf outright markets.
Exotic Bet
Any wager beyond a simple straight bet — parlays, teasers, props, and futures all qualify. They offer bigger payouts in exchange for a steeper house edge.
Handicap
A virtual head start or deficit applied to level an uneven matchup — the global term for what Americans call the point spread. Widely used in soccer betting.
If Bet
A sequence of wagers where each one is only placed if the previous bet wins or pushes. It lets you reinvest winnings down the chain while capping your exposure to the first stake.
Moneyline
A bet on which team or player wins outright, with no point spread involved. The odds reflect each side’s likelihood of winning.
Outright (Futures)
A bet on the eventual winner of a whole competition — a league title or tournament — rather than a single game. Also called a futures bet.
Parlay
A single bet that combines two or more selections, where every leg must win to pay out. The payout is larger, but so is the cumulative house edge.
Pick’em (PK)
A matchup with no favorite, where the spread is zero and you simply choose the winner. The payout sits near even money on both sides.
Point Spread
A handicap that the favorite must beat for a bet to win — laying -6.5 means the favorite must win by 7 or more. It levels the playing field between unequal teams.
Prop Bet
A wager on something other than the final result — a player’s stats, a team milestone, or an in-game event. Short for “proposition bet.”
Reverse
Two if-bets on the same selections running in opposite orders, so the conditional action triggers no matter which game settles first. It removes the sequencing risk of placing a single if bet.
Round Robin
A bet that automatically breaks a group of selections into every possible smaller parlay combination. Spreading the action this way means one losing leg need not sink your entire ticket.
Run Line
Baseball’s version of the point spread, almost always set at 1.5 runs. Backing a favorite on the run line means it must win by two or more.
Straight Bet
A single wager on one outcome — a moneyline, spread, or total — settled entirely on its own. The simplest and most common bet there is.
Teaser
A parlay variant that lets you shift the point spread or total in your favor on every leg, in exchange for a smaller payout. Each adjusted leg must still win for the bet to cash.
Totals (Over/Under)
A bet on whether the combined score of both teams will go over or under a number set by the book. The result of the game itself does not matter.
Prediction Markets
Event Contract
A CFTC-regulated contract that pays a fixed amount if a yes/no event happens and nothing if it doesn't. Its price, between $0 and $1, reflects the market's implied probability of that outcome.
Limit Order Book
The system prediction markets use to match buyers and sellers, listing every resting order to buy or sell a contract at a given price. A trade executes when a buy and a sell price meet.
Liquidity
The depth of buy and sell orders near the current price, which determines how large a position you can take without moving the market. Thin liquidity means wide spreads and more slippage.
Resolution
The settlement of a prediction-market contract once the real-world event is decided: the winning side is paid $1 per contract and the losing side gets nothing, based on a predefined source of truth.
Advanced
Bankroll Management
A systematic approach to sizing each bet as a small, consistent fraction of your total bankroll, so a cold streak can't wipe you out. It is the foundation every long-term bettor builds on.
Buying Points
Paying extra vig to move a spread or total in your favor — say from -7 to -6 — to get past a key number. The better number costs a worse price.
Closing Line Value (CLV)
The difference between the price you bet and the line when the market closes. Consistently beating the closing number is the clearest evidence that you are betting with a long-term edge.
Expected Value (EV)
The average profit or loss a bet would produce if you placed it many times. A positive-EV bet is one where your estimated edge beats the price you are getting.
Fading the Public
Deliberately betting against the side most casual bettors are backing, on the theory that heavy public money inflates the price on popular favorites. Often paired with reverse line movement as a confirming signal.
Flat Betting
Staking the same fixed amount on every wager regardless of confidence — the simplest form of bankroll management. It tames variance and makes your results easy to evaluate.
In-Play (Live Betting)
Betting on a game already underway, with odds recalculated in real time after every play. It rewards quick reads but demands discipline against impulsive wagers.
Kelly Criterion
A formula that sets your stake as a fraction of your bankroll based on your edge and the odds, to maximize long-term growth. Many bettors use a half- or quarter-Kelly stake to reduce swings.
Key Numbers
The margins games most often land on — 3 and 7 in the NFL — which makes spreads at those numbers far more valuable than the half-points around them.
Market Efficiency
How quickly and accurately a betting market absorbs new information into its prices. The more efficient the market, the harder it becomes to find mispriced lines to exploit.
Middle
Betting both sides of a line that has moved, so that a result landing in the gap wins both tickets. At worst you lose only the vig on one side.
Public Money
The collective action of casual bettors, who pile onto favorites, overs, and popular teams. Books shade those lines, and sharps fade the crowd.
Reverse Line Movement (RLM)
When a line moves opposite to where the public is betting — the favorite gets cheaper even though most tickets back it — signaling that sharp money sits on the other side.
Sharp Money
Bets placed by professional, winning players that books respect and react to. A line moving against the public is the classic fingerprint of sharp money.
Steam Move
A sudden, widespread line move driven by a wave of sharp money hitting a market at once, often across many books simultaneously. Chasing it after the fact usually means betting a worse number.