Glossary

A-Z reference of 49 sports betting terms. Use the search box to find a specific term.

Action

A bet or wager. "Having action" means you have an active bet on a game.

Against the Spread (ATS)

Betting on a team to cover the point spread, rather than just win outright.

Arbitrage

Placing bets on all outcomes of an event across different sportsbooks to guarantee a profit regardless of the result. Possible when odds discrepancies exist between books.

Bankroll

The total amount of money you have set aside for betting. Should be separate from everyday finances.

Betting Exchange

A platform where bettors bet against each other rather than against a sportsbook. Typically offers lower margins. Examples include Betfair.

Chalk

The favorite in a game. Betting on the chalk means betting on the team or player expected to win.

Closing Line

The final odds offered by a sportsbook just before an event starts. Widely considered the most accurate line.

Closing Line Value (CLV)

A measure of whether you got better odds than the closing line. Consistently beating the closing line is a strong indicator of long-term success.

Cover

Winning a bet against the point spread. A team "covers" when they win by more than the spread (favorite) or lose by less than the spread (underdog).

Decimal Odds

An odds format showing total return per unit staked, including the stake. Common in Canada and Europe. Example: 2.50 means $2.50 returned per $1 bet.

Drawdown

The peak-to-trough decline in your bankroll. A key risk metric. A 20% drawdown means your bankroll dropped 20% from its highest point.

Edge

The advantage a bettor has over the sportsbook. Calculated as the difference between estimated true probability and implied probability from the odds.

Expected Value (EV)

The average amount you expect to win or lose per bet over time. Positive EV (+EV) means a profitable bet in the long run.

Exposure

The total amount of money you have at risk across all open bets. Managing exposure prevents overcommitting your bankroll.

Favorite

The team or player expected to win, indicated by lower odds (or negative American odds).

Flat Betting

A staking strategy where you bet the same amount on every wager, regardless of confidence. The safest approach for beginners.

Futures

Long-term bets on outcomes determined at a later date, such as who will win a championship or league title.

Handle

The total amount of money wagered on an event across all bettors.

Hedge

Placing a bet on the opposite side of a previous bet to guarantee profit or minimize loss.

Implied Probability

The probability of an outcome as derived from the odds. Formula: 1 / decimal odds. Example: 2.00 odds = 50% implied probability.

In-Play (Live) Betting

Placing bets after an event has started. Odds change rapidly based on real-time developments in the game.

Juice

See Vig. The commission a sportsbook charges on a bet.

Kelly Criterion

A formula for calculating optimal bet size based on your estimated edge and the odds. Often used at a fraction (e.g., quarter Kelly) to reduce variance.

Line

The odds or point spread offered by a sportsbook for a particular bet.

Line Movement

Changes in the odds or spread between when a line opens and when the event starts. Driven by betting volume, news, and sharp action.

Line Shopping

Comparing odds across multiple sportsbooks to find the best available price. A fundamental practice for maximizing returns.

Lock

A bet that someone claims is guaranteed to win. There is no such thing as a lock. Be skeptical of anyone using this term.

Moneyline

A bet on which team or player will win outright, without a point spread.

No-Vig (Fair) Odds

The theoretical odds with the sportsbook's margin removed. Represents the true implied probability without the built-in commission.

Odds

Numbers that represent the payout ratio for a bet and the implied probability of an outcome.

Over/Under (Totals)

A bet on whether the combined score of both teams will be over or under a specified number set by the sportsbook.

Parlay

A bet combining two or more selections. All must win for the parlay to pay out. Higher potential payout but higher risk.

Point Spread

A margin of victory set by the sportsbook. The favorite must win by more than the spread; the underdog can lose by less than the spread.

Prop Bet

A bet on a specific event within a game rather than the final outcome. Examples: first player to score, total yards by a quarterback.

Push

A tie against the spread or total, where the result lands exactly on the number. Your stake is returned.

ROI (Return on Investment)

Your net profit divided by total amount wagered, expressed as a percentage. A key metric for measuring long-term performance.

Sharp

An experienced, professional bettor who consistently finds value. Sportsbooks track and often limit sharp bettors.

Square

A casual, recreational bettor. The opposite of a sharp.

Stake

The amount of money placed on a single bet.

Steam

Rapid, significant line movement caused by heavy betting action, often driven by sharp bettors.

Teaser

A type of parlay where you get adjusted point spreads in your favor on multiple games, in exchange for a lower payout.

Tout

Someone who sells betting picks or predictions. Quality varies widely. Be cautious of anyone guaranteeing profits.

Underdog

The team or player expected to lose, indicated by higher odds (or positive American odds).

Unit

A standard bet size, typically 1-3% of your total bankroll. Used to normalize bet sizing and track performance consistently.

Value Bet

A bet where the odds offered are higher than the true probability of the outcome. Finding value is the core of profitable betting.

Variance

The natural fluctuation in results due to randomness. Even with positive expected value, short-term results can deviate significantly from expectations.

Vig (Vigorish)

The commission or margin built into the odds by the sportsbook. Also called juice. It's how sportsbooks make money.

Void

A bet that is cancelled and your stake is returned. Can happen due to event cancellation, rule changes, or specific conditions not being met.

Wager

Another word for a bet.