Polymarket Parlays Glossary: Key Terms Explained
Every prediction market and parlay concept you need to know, explained in plain language.
Prediction markets have their own vocabulary. Whether you're a complete beginner or an experienced trader encountering a new term, this glossary covers every concept relevant to Polymarket parlay trading.
Terms are organized for progressive learning. Start from the top if you're new, or use your browser's search (Ctrl+F / Cmd+F) to jump to a specific term.
Parlay
A combined bet linking two or more independent outcomes into a single position. All legs must win for the parlay to achieve its maximum return. Also called an accumulator or multi-bet in other markets.
Leg
A single individual bet within a parlay. Each leg corresponds to one market position. A 3-leg parlay has three separate market positions that must all resolve in your favor.
Resolution
The process by which a prediction market determines the outcome of an event. On Polymarket, resolution is handled by UMA's optimistic oracle, which uses decentralized verification with a dispute mechanism.
CLOB (Central Limit Order Book)
The order matching system used by Polymarket. Buyers and sellers place limit orders at specific prices, and the CLOB matches them. Unlike automated market makers (AMMs), CLOBs provide tighter spreads and better price discovery.
Liquidity
The depth of buy and sell orders in a market. High liquidity means you can enter and exit large positions without significantly moving the price. Low liquidity means even small trades can cause slippage.
Implied Probability
The probability of an outcome as suggested by the market price. A share priced at $0.65 implies a 65% probability of that outcome occurring. Parlay traders look for legs where their estimated probability exceeds the implied probability.
Expected Value (EV)
The average outcome of a bet if repeated many times. Calculated as (probability of winning x payout) minus (probability of losing x cost). Positive EV bets are profitable long-term. Negative EV bets lose money over time.
Hedging
Reducing risk by taking an offsetting position. In parlays, you can hedge by selling shares in one leg that has moved in your favor, or by buying the opposite side of a leg you're uncertain about. Hedging locks in partial profits at the cost of reducing maximum upside.
Arbitrage
Exploiting price discrepancies between related markets for a risk-free or near-risk-free profit. On Polymarket, arbitrage can occur when complementary markets (e.g., Yes/No on the same event across different market listings) are temporarily mispriced.
Market Maker
A trader or bot that provides liquidity by placing both buy and sell orders around the current market price. Market makers profit from the bid-ask spread and are essential for maintaining liquid, tradeable markets.
Slippage
The difference between the expected price of a trade and the actual execution price. Slippage occurs in low-liquidity markets or with large order sizes. In parlays, slippage on each leg compounds across all legs.
Bid-Ask Spread
The difference between the highest price a buyer is willing to pay (bid) and the lowest price a seller is willing to accept (ask). Tighter spreads indicate better liquidity and lower trading costs.
Kelly Criterion
A mathematical formula for determining the optimal bet size to maximize long-term bankroll growth. For parlays, a modified version (typically quarter-Kelly) is used to account for the higher variance of multi-leg bets.
Vigorish (Vig)
The fee or margin built into a bet by the bookmaker. Traditional sportsbooks charge 5-10% vig. Polymarket's CLOB structure has significantly lower effective vig (1-3%), making it more favorable for parlay construction.
Correlation
The degree to which two events are related. Positively correlated legs tend to win or lose together. Negatively correlated legs move in opposite directions. Uncorrelated legs are independent. Correlation affects the true combined probability of a parlay.
Bankroll
The total amount of capital you have allocated to prediction market trading. Proper bankroll management (never risking more than 3-5% per parlay) is essential for surviving the high variance inherent in multi-leg betting.
Optimistic Oracle
The resolution mechanism used by Polymarket, powered by UMA. A proposer submits an outcome with a bond. If no one disputes within the challenge period, the outcome is accepted. If disputed, UMA token holders vote on the correct resolution.
Polygon
The blockchain network on which Polymarket operates. Polygon is an Ethereum Layer 2 scaling solution that offers fast, low-cost transactions. All Polymarket trades settle on Polygon, with positions held in the user's wallet.
USDC
USD Coin, the stablecoin used for all trading on Polymarket. USDC is pegged 1:1 to the U.S. dollar and is issued by Circle. All Polymarket positions are denominated in USDC.
Conditional Token
The ERC-1155 token standard used by Polymarket for representing market positions. Each outcome (Yes/No) in a market has its own conditional token. When a market resolves, winning tokens can be redeemed for $1.00 USDC each.
Position Sizing
Determining how much capital to allocate to a specific trade or parlay. Proper position sizing balances the potential return against the risk of loss, ensuring that no single trade can significantly damage your overall bankroll.
Break-Even Probability
The minimum probability at which a bet becomes profitable. For a share priced at $0.40, the break-even probability is 40%. If you believe the true probability exceeds 40%, the bet has positive expected value.
Maker vs Taker
A maker adds liquidity by placing limit orders that rest on the order book. A taker removes liquidity by placing market orders that execute against resting orders. Makers typically pay lower fees than takers on Polymarket.
Learn More
Understanding these terms is just the beginning. Apply them in practice with our beginner's guide, or level up with advanced strategies. For current opportunities using these concepts, check the best parlays of 2026.
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