Sports betting has its own language, and not knowing it puts you at a disadvantage before you place a single bet. This glossary covers every term a beginner needs, explained through the lens of +EV betting.
For a quick, searchable version, see the interactive glossary on our homepage.
Core Concepts
Bankroll (Purse)
The total amount of money set aside specifically for betting, completely separate from your personal finances. Your purse is not your paycheck. It's money you can afford to lose entirely.
Unit
A standard bet size, typically 1% of your bankroll. If your purse is $2,000, one unit is $20. Units keep your bets proportional and protect you from ruin.
+EV (Positive Expected Value)
A bet where your estimated probability of winning is higher than the implied probability from the odds. The only type of bet worth making.
-EV (Negative Expected Value)
A bet where the odds don't offer enough value relative to the true probability. Over time, -EV bets lose money. Most bets offered by sportsbooks are -EV by design.
Vig (Vigorish / Juice)
The sportsbook's built-in commission on every bet. At standard -110 odds, the vig is about 4.5%.
Implied Probability
The probability of an outcome as suggested by the odds, with the vig included. -200 odds imply 66.7%. +150 implies 40%.
Bet Types
Moneyline
A bet on which team or player wins outright. No spread, no conditions — just pick the winner.
Point Spread (Spread)
A bet on the margin of victory. The favorite must win by more than the spread; the underdog can lose by less than the spread or win outright.
Over/Under (Total)
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 two or more wagers. Every leg must win. Payouts are higher because the vig compounds — which is why parlays are usually -EV.
Same-Game Parlay (SGP)
A parlay where all legs are from the same game. The sportsbook prices in correlation, usually to your disadvantage.
Prop Bet
A bet on a specific event within a game (player yards, touchdowns, strikeouts), not the final outcome. Often less efficient than main lines — where sharp bettors find edge.
Futures
A bet on something decided in the future — championship winners, MVP, season win totals. Your money is locked up until the outcome is determined.
Teaser
A parlay where you adjust the spread in your favor on every leg, in exchange for lower payouts. Common in football.
Live Bet (In-Play)
A bet placed while the game is in progress. Odds change in real time. The vig is typically higher than pre-game.
Odds & Lines
American Odds
US standard. Negative numbers (-150) show how much you risk to win $100. Positive numbers (+130) show how much you win on $100.
Decimal Odds
Common in Europe. The total return per dollar wagered. 2.50 = $2.50 back per $1 bet.
Fractional Odds
UK format. 5/1 means $5 profit per $1 wagered. 10/11 equals -110 in American.
Favorite
The team or player expected to win. Marked with a minus sign (-). Lower payouts.
Underdog
The team or player expected to lose. Marked with a plus sign (+). Higher payouts.
Hook
A half-point in the spread. Getting +3.5 instead of +3 means you "got the hook." That half-point matters enormously in football.
Push
When the result lands exactly on the spread or total. Your bet is refunded.
Chalk
Slang for the favorite. "Betting the chalk" means betting favorites.
Strategy Terms
Closing Line Value (CLV)
Whether you got better odds than the final closing line. The strongest predictor of long-term profitability.
Line Shopping
Comparing odds across multiple sportsbooks to find the best price. The easiest free edge in betting.
Kelly Criterion
A formula for optimal bet sizing based on your edge. Most pros use fractional Kelly.
Flat Betting
Wagering the same amount (1 unit) on every bet. The simplest, most sustainable bankroll strategy.
Hedge
Placing a second bet on the opposite side to guarantee profit or reduce risk.
Arbitrage (Arb)
Betting both sides across different sportsbooks when odds create a guaranteed profit regardless of outcome.
Sharp
A professional, winning bettor whose action sportsbooks track and respect.
Square
A recreational bettor. Not an insult — most people bet for fun. This site helps you move from square toward sharp.
Steam Move
A sudden, significant line movement caused by heavy sharp action.
Reverse Line Movement
When the line moves opposite to where the majority of public bets are placed — usually a signal of sharp money on the other side.
Tout
Someone who sells betting picks. Most are not profitable long-term. Be skeptical.
Action
Having a bet in play. "I've got action on the Chiefs" means you have an active wager.
Handle
The total dollar amount wagered on an event or at a sportsbook.
No-Vig Line (Fair Odds)
Theoretical odds with the sportsbook's commission removed. Reveals the "true" market price.
ATS (Against the Spread)
A team's record when measured against the point spread, not just wins and losses. A team can be 3-7 straight up but 7-3 ATS.
Bookmark this page. Come back whenever you encounter a term you don't recognize. And for instant lookups, use the searchable glossary on our homepage.
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