Glossary
The betting market, defined precisely.
Last updated 2026-07-04
Every term gets a direct answer, the underlying math, and the API call that computes it against live multi-book data. 21 terms and growing.
Closing Line Value (CLV)
Closing line value is the difference, in implied probability, between the price you bet and the market's final price before the game starts. Consisten...
Steam Move
A steam move is a sudden, coordinated line change across many sportsbooks at nearly the same time, usually triggered by heavy sharp action. When ten b...
Vig (Juice)
Vig, short for vigorish and also called juice, is the bookmaker's built-in margin. The implied probabilities of all outcomes in a market sum to more t...
Hold
Hold is the percentage of total money wagered that a sportsbook expects to keep, determined by the vig baked into its prices. A market whose implied p...
No-Vig Fair Odds (De-vigging)
No-vig fair odds are a market's prices with the bookmaker margin stripped out, recovering the book's true probability estimate. De-vigging divides eac...
Reverse Line Movement
Reverse line movement is when a betting line moves against the majority of bets: 70% of tickets are on one team, yet the line moves toward the other s...
Sharp Money
Sharp money is action from bettors and syndicates with a proven long-term edge, whose wagers move lines. Books identify these accounts, limit them at ...
Key Numbers
Key numbers are the final margins that occur most often in a sport, making them the most valuable points to cross when buying or selling a line. In th...
Alternate Lines
Alternate lines are versions of a spread or total offered at points other than the main number, with prices adjusted to compensate. Instead of -7.5 at...
Consensus Line
The consensus line is the market's central price for an outcome, computed as the median or mean across many sportsbooks. It smooths out any single boo...
Opening Line
The opening line is the first price a sportsbook posts for a game, before public and sharp money begin shaping it. Openers are the linemaker's raw opi...
Closing Line
The closing line is the final price available on a market before the event starts. It is the market's most informed number, incorporating every bet, i...
Implied Probability
Implied probability is the win chance embedded in a betting price: 1 divided by the decimal odds. Decimal odds of 2.50 (+150 American) imply 40%. Beca...
Fair Odds vs Market Odds
Market odds are the prices books actually offer, vig included. Fair odds are the estimate of what prices would be with no margin and no book positioni...
Expected Value (+EV)
Expected value is the average profit or loss of a bet if it were repeated many times: (win probability x amount won) minus (loss probability x stake)....
Arbitrage (Arbing)
Sports betting arbitrage is backing every outcome of an event at different sportsbooks whose combined implied probability is under 100%, guaranteeing ...
Middling
Middling is betting both sides of a game at different numbers so that some final margins win both bets. Take a favorite at -2.5 early and the underdog...
Betting Limits
Betting limits are the maximum stake a sportsbook will accept on a market, and they are information: books post low limits when their number is uncert...
Market Efficiency
A betting market is efficient when its prices fully reflect available information, leaving no systematic profit after vig. Major markets approach effi...
Line Shopping
Line shopping is checking the same bet's price at many sportsbooks and taking the best one. It is the single highest-return habit available to any bet...
Juice
Juice is slang for the bookmaker's commission, identical to vig: the margin built into prices so that implied probabilities sum past 100%. "Reduced ju...
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