Course Introduction
By Cadell Griffith, Software Architect and founder of OddsFantasy · Updated · 5 min read
A sports betting glossary defines the words you meet on every bookmaker and trading screen, from odds, stake and payout to vig, expected value and closing line value. This one explains 50 betting and trading terms in plain English, and every term links to the lesson or calculator that covers it in depth.
Accumulator (Parlay):
A type of bet that combines multiple selections into one wager. All selections must win for the bet to be successful.
Arbitrage (Surebet):
A betting strategy where you place bets on all possible outcomes of an event at different bookmakers, sized so that you profit whichever outcome wins.
Arbitrage Calculator:
A tool that splits a total stake across every outcome of an arbitrage so each outcome returns the same payout.
Bankroll:
The total amount of money you’ve set aside for betting activities.
Bet Tracking:
The practice of recording your bets including stake, odds, and results to analyze performance and identify strengths and weaknesses.
Bookmaking:
The process by which a bookmaker sets odds, accepts bets, and manages risk.
Bookmaker (Bookie):
A company or individual that offers odds on sporting events and accepts wagers.
Balanced Book:
A situation where a bookmaker has proportionally equal money on all outcomes, ensuring profit from the margin regardless of the result.
CLV (Closing Line Value):
How much better your odds were than the closing odds, the last price before the event starts. Beating the closing line is the strongest sign that your bets have an edge.
Confidence-Based Sizing:
Adjusting your bet size based on how confident you are in your edge or your assessment of the true odds.
Data-Driven Betting:
An approach to sports betting that relies on data, probabilities, and expected value rather than emotions or guesses.
Drawdown (Max Drawdown):
The largest drop in your bankroll from its highest point to a subsequent low point before it recovers.
Edge:
Your advantage over the bookmaker, usually expressed as a percentage (Expected Value). A positive edge means a profitable opportunity in the long run.
Event:
The specific match or contest you’re betting on (e.g., Real Madrid vs. Manchester City).
EV (Expected Value):
A measure of the average return you can expect from a bet over time. Positive EV means profitable in the long run; negative EV means losses.
EV Simulator:
A tool that runs simulations to visualize bankroll growth and performance based on your edge and strategy.
Exchange (Betting Exchange):
A marketplace where bettors trade against each other instead of against a bookmaker. The exchange charges a commission on winnings rather than building a margin into the odds.
Hedge:
A bet or trade on the opposite side of an open position that reduces or locks in its result before the event ends.
Kelly Criterion:
A mathematical formula used to determine the optimal amount of your bankroll to wager based on your edge and odds. Helps maximize growth while managing risk.
Kelly Multiplier:
A factor used to scale down the Kelly stake to reduce volatility (e.g., 0.25 Kelly = 25% of the full Kelly stake).
Limit Order:
An order on an exchange or prediction market that only fills at the odds you choose or better, and waits in the order book until it is matched, cancelled or expires.
Limits:
The maximum amount a bookmaker allows you to stake on a specific market or outcome.
Line (or Odds Line):
Represents the bookmaker’s view of the probability of an outcome. “Sharp lines” are accurate reflections of true probabilities.
Line Movement:
A change in the odds of an outcome over time, caused by money, new information or a bookmaker copying a sharper price.
Liquidity:
The total amount of money available in a market. High liquidity markets allow larger bets with minimal odds movement.
Margin (Vig or Juice):
The bookmaker’s built-in profit on a market. It’s the difference between the total implied probability and 100%.
Market:
A specific category of bets within an event (e.g., Both Teams to Score, Over/Under Goals, Money Line).
Market Limit:
The maximum total amount that can be wagered on a market before the bookmaker adjusts the odds.
Odds (Price):
A number representing the likelihood of an event occurring, used to calculate potential payouts.
Order Book:
The list of open buy and sell orders on an exchange or prediction market, showing how much can be traded at each price.
Outcome:
The specific result you are betting on (e.g., Team A to win, Over 3.5 goals).
Payout:
The total amount returned on a winning bet (Stake × Odds).
Positive Expected Value (Positive EV):
A situation where the proposed odds are greater than the true odds.
Prediction Market:
An exchange, such as Polymarket, where you buy and sell shares in an outcome. A share pays $1 if the outcome happens, so a price of $0.40 equals decimal odds of 2.50.
Professional Punter:
A bettor who treats betting as an investment and uses data, strategy, and bankroll management to achieve consistent profits.
Sharp Bookmaker:
A bookmaker known for accurate odds, low margins, and high limits (e.g., Pinnacle). Attracts professional bettors.
Simulation:
A computational model used to test betting strategies over a large number of bets to visualize long-term outcomes.
Soft Bookmaker:
A bookmaker with slower-moving odds, higher margins, and lower limits, often aimed at casual bettors (e.g., Stake, SportyBet).
Spread (Bid-Ask Spread):
On an exchange or prediction market, the gap between the best price to buy and the best price to sell. A wide spread makes it more expensive to enter and exit.
Staking Strategy:
A structured approach to determining how much to bet on each wager, often based on bankroll and confidence.
Stake:
The amount of money you risk on a single bet.
Steam Move:
A fast, large odds move across many bookmakers at once, usually after sharp money hits the market.
Stop-Loss:
An instruction to close a position automatically once its loss reaches a set level.
Strategy:
A defined approach or system for selecting bets, managing bankroll, and maximizing profit.
Take-Profit:
An instruction to close a position automatically once its profit reaches a set level.
True Probability:
The actual chance of an outcome occurring, expressed as a percentage (1 / True Odds).
Value Bet:
A bet whose odds are higher than the fair, no-vig odds, so it has positive expected value.
Variance:
The level of fluctuation in your betting results. Higher variance = bigger swings in profit/loss.
Vig (Juice or Margin):
The bookmaker’s fee built into the odds, which makes the implied probabilities of a market add up to more than 100%.