Reference

The complete sports betting glossary

Every term you'll see at a sportsbook, in a betting podcast, or on Parlae — defined in plain English. Organized by category. 59 entries.

Wager types Pricing & value Market Outcomes Strategy Roles Industry

Wager types

Moneyline: A bet on which side wins outright. American odds quote the price as a negative number for favorites (the amount you must risk to win $100) and a positive number for underdogs (the amount you win on a $100 risk).
Point spread(Spread, Line, ATS): A handicap added to or subtracted from a team's final score to balance betting on both sides. The favorite must win by more than the spread; the underdog wins (or 'covers') if they lose by less than the spread or win outright.
Total(Over/Under, O/U): A bet on whether the combined score of both teams will be over or under a number set by the sportsbook.
Parlay: A single bet combining multiple selections, all of which must win for the parlay to pay. Payouts compound but so does vig.
Same-game parlay(SGP): A parlay built entirely from selections within a single game. Books re-price for correlation, which typically increases hold.
Teaser: A multi-leg bet where you 'buy' points on every leg (e.g. moving NFL spreads 6 points) in exchange for reduced odds.
Round robin: A group of smaller parlays generated from a larger set of selections. A 3-team round robin produces three 2-team parlays.
Prop bet(Proposition): A wager on something other than the final outcome — typically a player stat (rushing yards, three-pointers made) or a game event (first scoring play, coin toss).
Futures: A wager on a long-term outcome decided weeks or months later, such as a championship winner, MVP, or season win totals.
Live bet(In-play): A wager placed after a game has started, with odds updating in real time as game state changes.
Pleaser: The opposite of a teaser — you move the line against yourself in exchange for boosted odds.
If bet: A conditional sequence where the next bet only places if the previous one wins, limiting risk if your first selection loses.

Pricing & value

American odds(US odds): Odds expressed in +/− cents per $100. Favorites use minus signs (risk this much to win $100), underdogs use plus signs (win this much on $100 risked).
Decimal odds: Odds shown as a multiplier of stake including the original wager. 2.50 decimal = +150 American = 3/2 fractional.
Fractional odds: UK-style odds shown as profit-to-stake (e.g. 5/2 means $5 profit for every $2 risked).
Implied probability: The win probability encoded in the price. = 1 / decimal odds. -110 implies 52.38%.
Vig(Juice, Hold, Margin): The sportsbook's built-in margin. Sum the implied probabilities of every outcome — anything above 100% is the vig.
No-vig price(Fair odds): The price after removing the book's margin — the closest proxy to true probability.
+EV(Positive EV, Expected value): A bet whose expected long-run return is positive after vig. Found by comparing your estimated true probability to the implied probability of the offered price.
-EV: A bet whose expected long-run return is negative. Every standard sportsbook bet at posted prices is -EV unless you've found an edge.
Closing line value(CLV): The difference between the price you bet and the closing price. Consistent positive CLV is the single best long-term proxy for being a winning bettor.
Sharp line: Pricing from books that take large action from professionals (Pinnacle, Circa, Bookmaker). Sharp lines are widely considered the most efficient.
Soft line: Pricing from a recreational book that hasn't moved to the consensus. Soft lines are where +EV is found.

Market

Line movement: Change in posted odds over time, typically driven by money taken on one side or new information (injuries, weather, lineup changes).
Steam move: Sharp, rapid movement of a line at multiple books simultaneously, usually triggered by syndicate action.
Reverse line movement(RLM): When a line moves opposite the betting public — e.g. 80% of bets are on Team A but the spread moves toward Team B. Often signals sharp money on B.
Sharp money: Bets placed by professional bettors and syndicates. Books track sharp action carefully and adjust lines accordingly.
Square money(Public money): Bets from recreational players, typically biased toward favorites, overs, and prime-time teams.
Opener: The first line posted on a market, often by a small number of sharp shops, before mass-market books copy.
Closer(Closing line): The final price before a market locks at game time. The closer is the most efficient line of the cycle.
Limit: The maximum a sportsbook will accept on a single wager. Sharp books take high limits; recreational books take low limits.
Key number: A common margin of victory worth more than other numbers. NFL: 3 and 7 are by far the most important. NBA: smaller spikes around even numbers.

Outcomes

Push: When a bet ties (e.g. a -3 spread when the favorite wins by exactly 3). Stake is returned; no profit, no loss.
Cover: Winning a spread bet — the favorite won by more than the spread, or the underdog lost by less (or won outright).
Backdoor cover: A meaningless late score that flips the spread result. Notorious source of bad beats.
Bad beat: Losing a bet in an unusually painful way — typically a late-game swing on a play that doesn't affect the actual outcome.
Void(No action): A bet that's cancelled and refunded — typically due to a player not starting, a game being postponed, or rule conditions not being met.

Strategy

Bankroll: The total amount of money set aside specifically for wagering. Should be separate from rent/bill money and treated as risk capital.
Unit: A standard bet size, typically 1–2% of bankroll. Using units lets you communicate bet sizing independent of account size.
Kelly criterion: A bet-sizing formula that recommends staking a fraction of bankroll proportional to your edge. Full Kelly maximizes log-growth but with high variance — most bettors use quarter or half Kelly.
Hedge: Placing a bet on the opposite side of an existing position to reduce risk or lock in profit, usually at the cost of EV.
Arbitrage(Arb): Placing opposing bets at different books where the prices guarantee a profit regardless of outcome. Yields are usually 0.5–2%.
Middle: When two opposing lines at different books create a window where both bets can win. E.g. bet +3.5 at Book A, -2.5 at Book B; if the favorite wins by 3, both cash.
Scalping: Trading small margins on opposing markets, similar to arbitrage but executed actively as lines move.
Devig: Removing the book's margin from a two-sided market to estimate true probabilities for each side.
Line shopping: Comparing the same market across multiple books to bet the best available price. Single most important habit for long-term profit.
Bonus bet(Free bet): A promotional credit that returns only profit (not stake) if your wager wins. Worth roughly 60–80% of face value.
Promo abuse(Bonus bagging): Systematically converting sportsbook promotions to expected value, typically via hedging across books. Legal but books may limit or close accounts.

Roles

Sharp: A long-term winning bettor — usually defined by sustained positive closing line value rather than short-term ROI.
Square: A recreational bettor who bets primarily for fun rather than profit. Books are happy to accept square action without limits.
Whale: A high-volume recreational bettor. Books typically extend high limits and bonus offers.
Runner: Someone who places bets at retail sportsbooks on behalf of a syndicate or sharp who can't bet themselves (often due to limits).
Beard: A person who uses someone else's identity to place bets — typically because the actual bettor is limited or banned.

Industry

Sportsbook: A licensed operator that accepts wagers. In the US, mobile sportsbooks are licensed at the state level.
Handle: The total amount wagered in a market or at a sportsbook over a given period — not the same as revenue.
Hold percentage: A book's revenue as a percentage of total handle. US books typically hold 7–9% of all dollars wagered.
GGR(Gross gaming revenue): Sportsbook winnings before promotional deductions or operating costs. The base most state tax rates apply to.
Cashout: An option offered by some books to settle an active wager early for less than the potential payout. Almost always -EV.
Voided promo: A promotional credit revoked by a sportsbook, typically when terms are violated or the book retroactively deems the bet ineligible.