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Betting glossary

Plain-English definitions • Updated 18 Oct 2026

The terms you'll meet on SureBetUK, in plain English, with links to the guides that go deeper.

Accumulator (acca)

One bet combining selections from different matches; all must win. Its price is the single prices multiplied together. Bet builder vs accumulator.

Arbitrage (arb, sure bet)

Backing every outcome of an event at prices that disagree enough to guarantee a profit whatever happens. What is arbitrage betting?

Back bet

An ordinary bet that something will happen. You "back" a team to win.

Back/lay arb

An arb made by backing an outcome with a bookmaker and laying the same outcome for less on a betting exchange. Back/lay arbitrage explained.

Bet builder (same-game multi)

One bet combining several selections from the same match, such as three players each to have a shot on target. All must win, and the legs are priced together because they're linked. What is a bet builder?

Betting exchange

A marketplace where customers bet against each other rather than against a bookmaker, such as Betfair Exchange, Matchbook or Smarkets. The exchange charges commission on winnings.

Bookmaker margin

The bookmaker's built-in edge: how far the implied chances of every outcome add up to more than 100%. Margin calculator.

Commission

The percentage an exchange takes from net winnings on a market. Our arb maths always includes it.

Confirmed line-up

The official starting eleven, usually published about an hour before kick-off. Our bet builder tips are only built from confirmed line-ups.

Correlation

How much two outcomes tend to happen together. Legs in the same match are correlated, which is why a bet builder isn't priced by multiplying its legs. How bookmakers price bet builders.

Decimal odds

The total return for every £1 staked, stake included. Odds of 3.00 return £3 for £1. Odds converter.

Edge

How much better a price is than fair, as a percentage. Odds of 3.30 against a fair 3.00 is a 10% edge.

Expected value (EV)

What a bet is worth on average over many repeats: your edge multiplied by your stake. A £10 bet with a 5% edge has an expected value of +50p. Value bet calculator.

Fair odds

The price a bet would have with no margin: 1 divided by its true chance. At fair odds you break even over time. Every bet builder slip we post shows its fair odds. Fair odds explained.

Fractional odds

Profit against stake, the traditional UK format: 5/2 means £5 profit for every £2 staked.

Gubbing

Slang for a bookmaker restricting an account, usually by limiting stakes, often after a run of value or arb bets. How bookmakers spot arbers.

Implied probability

The chance a price suggests, before margin comes out: 1 divided by the decimal odds. Odds of 4.00 imply 25%.

Lay bet

A bet that something will not happen, made on a betting exchange. When you lay, you act as the bookmaker.

Liability

What you stand to lose on a lay bet if the outcome happens: your lay stake multiplied by the odds minus one.

Matched betting

Using bookmakers' free bets and offers, laid off on an exchange, to extract their value. Different from arbing, which needs no offers. Arbitrage vs matched betting.

Overround

The total of a market's implied chances. Anything over 100% is the bookmaker's margin: 104.8% means a 4.8% margin.

Sharp bookmaker

A bookmaker whose prices are moved by well-informed money and who keeps margins low, so its prices are a good guide to fair odds. Our value alerts compare soft bookmakers against a sharp line.

Shot on target

An attempt that would have gone in without a save or a last-ditch block: goals, saved shots and goal-line clearances count; shots that hit the woodwork and stay out don't. Shots on target betting explained.

Soft bookmaker

A mainstream bookmaker aimed at recreational customers, whose prices are slower to move and more likely to be out of line — the source of most arbs and value bets.

Stake

The amount you bet.

Treble

A bet with three selections that must all win. Our bet builder slips are trebles from one match.

Value bet

A bet whose price is higher than its fair odds — bigger than the outcome's real chance justifies. Value bets win and lose, but come out ahead over many bets.

Void

A bet or leg that's cancelled and treated as if it never happened, usually because an event didn't take place or a player took no part. Rules vary between bookmakers, especially for bet builders.