Sports Betting Glossary
Plain-English definitions for every sports betting term — moneyline, spread, CLV, Kelly, EV, and 100+ more. With worked examples and calculator links.
126 terms across 8 categories
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Odds Formats & Probability
- American Odds popular US +/− odds showing payout per $100.
- Decimal Odds popular Odds as a stake multiplier (2.50).
- Fractional Odds UK fraction (5/1) of profit to stake.
- Implied Probability popular Win % baked into a price.
- Breakeven Win Rate Hit-rate needed to profit (52.4% at −110).
- Odds Conversion Translating among formats + probability.
- Plus Money Positive price (+150) paying > stake.
- Minus Money Negative price (−150).
- Payout Total returned on a win (stake + profit).
Bet Types
- Moneyline popular Straight bet on who wins.
- Point Spread popular Handicap the favorite must cover.
- Over/Under popular Bet on combined points vs a number.
- Parlay popular Multi-leg bet; all must win.
- Teaser Parlay moving lines in your favor for lower odds.
- Prop Bet popular Wager on a specific event not final score.
- Player Prop Prop on an individual stat line.
- Futures Bet popular Long-horizon season-outcome bet.
- Round Robin Auto set of smaller parlays from a pool.
- If-Bet Next leg fires only if prior wins.
- Reverse Bet Two-way if-bets both orderings.
- Same-Game Parlay Parlay of correlated legs in one game.
- Straight Bet Single wager on one outcome.
- Live (In-Play) Bet Wager after start on shifting odds.
- Pleaser Reverse teaser, lines against you, boosted payout.
- First-Half/Quarter Bet on a partial-game segment.
Market Mechanics
- Vig (Vigorish) popular Book's built-in commission.
- Juice popular Slang for vig; cost of betting.
- No-Vig (Fair) Odds popular True price with margin stripped.
- Hold Book's expected % across a balanced market.
- Betting Line Current price/handicap offered.
- Opening Line First line posted.
- Closing Line popular Final line before kickoff.
- Steam Move Fast league-wide move from synced money.
- Reverse Line Movement Line vs public % — sharp signal.
- Limit Max stake a book accepts.
- Line Shopping Comparing books for best number.
- Off the Board Market pulled, no bets taken.
- Buying Points Extra juice to move a number.
- Push Tie against the number, stake refunded.
- Key Number Common margin (3,7 NFL) lines cluster on.
- Market A wager type/event a book prices.
- Two-Way/Three-Way 2 outcomes vs one allowing a draw.
- Handle Total dollar volume wagered.
- Balanced Book Even action; book profits on vig.
Bankroll & Staking
- Unit popular Standardized bet size (~1% bankroll).
- Kelly Criterion popular Formula sizing bets by edge.
- Fractional Kelly Fraction of full Kelly to cut variance.
- Bankroll popular Money set aside for betting.
- Flat Betting Same amount every play.
- ROI popular Profit ÷ amount risked.
- Yield Profit as % of total stakes.
- Variance popular Natural swings around expectation.
- Drawdown Peak-to-trough bankroll drop.
- Stake Money on a single bet.
- Risk of Ruin Probability of busting given stake + edge.
- Bankroll Management Staking discipline to survive variance.
- Win Rate Share of bets that win.
- Profit Net won after stakes.
Sharp Concepts
- Closing Line Value (CLV) popular Beating the close; best edge proxy.
- Expected Value (EV) popular Avg profit/loss if repeated forever.
- +EV (Positive EV) popular Bet priced better than true prob.
- Edge popular Probability advantage over the price.
- Middling Both sides at diff numbers to win both.
- Arbitrage popular Bets on all outcomes across books where prices disagree.
- Hedging popular Opposite side to narrow the range of outcomes.
- Sharp Money popular Pro wagers that move lines.
- Square Money Recreational action books fade.
- Public Fade Betting against public consensus.
- Sharp Bettor Consistently profitable pro.
- Beard Proxy placing bets for an anonymous sharp.
- Steam Chasing Following a steam move for the old number.
- Fair Value No-vig true price to measure against.
- Synthetic Hold Margin from combining lines across books.
- Free Bet Conversion Promo free bet -> cash via hedging.
DFS Terms
- GPP (Tournament) popular Guaranteed-prize-pool top-heavy contest.
- Cash Game Flat-payout contest rewarding consistency.
- Leverage popular Edge via over/underweight vs field.
- Ownership popular % of lineups rostering a player.
- Stacking Pairing correlated players for upside.
- Late Swap Editing slots before each lock.
- Salary Cap DFS budget across slots.
- Chalk Heavily owned popular play.
- Contrarian Play Low-owned differentiator.
- Bring-Back Opposing-team piece in a game stack.
- Game Stack Players from both sides of one game.
- Floor Reliable low-end output.
- Ceiling Tournament-winning upside.
- Min-Cash Just inside paid GPP places.
- Field Aggregate of opposing lineups.
- Pivot Swap chalk for lower-owned at similar cost.
- Value Play Low-salary player beating cost.
- Pick'em (Player DFS) More/less prop-style DFS.
Stats & Modeling
- Regression to the Mean Extremes tend back to averages.
- Correlation How strongly outcomes move together.
- Sample Size Observations needed for meaning.
- Brier Score Probability-forecast accuracy (lower better).
- Calibration Predicted probs match real hit rates.
- Standard Deviation Spread of outcomes around average.
- Confidence Interval Range likely to contain true value.
- Backtesting Replaying a strategy on history.
- Overfitting Model memorizing noise, failing live.
- Probability Model System estimating outcome odds.
- Z-Score Std devs from the mean.
- Power Rating Team strength number for spreads.
- Monte Carlo Simulation Thousands of random trials for odds.
- Mean / Expectation Long-run average of an outcome.
- EPA (Expected Points Added) Change in a team's expected points caused by one play.
- Success Rate Share of plays that reach a yardage target for their down and distance.
- Pace How many plays or possessions a team runs per unit of time.
- Elo Rating Team strength number that moves after each result, scaled by opponent strength.
- Target Share Share of a team's pass targets that go to one player.
Beginner & Catch-all
- Favorite Side expected to win, minus odds.
- Underdog Side expected to lose, plus odds.
- Cover Winning after the point spread is applied to the team score.
- ATS Record relative to the spread.
- Pick'em Zero spread; pick the winner.
- Chalk (Betting) Backing the heavy favorite.
- Bad Beat Near-certain win lost on a fluke.
- Lock Mistaken "sure thing" — none exist.
- Tout Pick seller, rarely with a real edge.
- Sportsbook Licensed operator taking bets.
- Cash Out Settling a bet early for an offer.
- Action Money at risk on an outcome.
- Odds Boost Promo paying enhanced odds.
- Parlay Boost Promo multiplier on a parlay.
- Correlated Parlay Parlay with statistically linked legs.
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