Betting terms, plain

A single bet that combines four or more selections. All selections must win for the bet to pay out. The odds multiply together, creating the potential for large returns from a small stake, though the risk increases with each added selection.

A bet placed in advance of the day of the race, often weeks or months before the event. Ante-post odds are typically more generous because you take on the additional risk that your selection may not run. Most ante-post bets are non-refundable if the horse is withdrawn.

A bookmaker offer that refunds your accumulator stake (usually as a free bet) if one leg lets you down. It softens the loss but doesn't change the odds stacked into the acca in the first place.

A promotion offered by many bookmakers where, if you take a price on a horse and the Starting Price (SP) is higher, you'll be paid out at the better odds. This only applies to bets placed on the day of the race, not ante-post wagers.

A measure of how accurate a probability forecast is. For every prediction, take the gap between the stated chance and what actually happened (1 for a win, 0 otherwise), square it, and average across all predictions. Lower is better, and confident misses are punished hardest, so the only way to score well is to give every runner its honest chance. It is how serious forecasters are graded, and how the AI Lab scores its model against the betting market.

The starting price worked out by the Betfair exchange from its back and lay bets at the off (BSP). It is often bigger than the bookmakers' official SP, which is why the Lab settles to the tougher industry SP.

To bet on something to happen, the ordinary bet: you back a horse to win. The opposite of laying.

A National Hunt Flat race, run on the level for jumps-bred horses that have not yet raced over hurdles or fences. A first look at future jumpers.

The five most prestigious Flat races for three-year-olds: the 2,000 and 1,000 Guineas, the Oaks, the Derby and the St Leger.

A bet on two selections in different events. Both must win for the bet to be successful. The winnings from the first selection are automatically reinvested on the second, meaning returns can be significantly higher than two single bets.

Odds shown as a single number that already includes your stake, like 6.0. Stake times the decimal is your total return, so 6.0 is the same as 5/1. Common on exchanges and abroad.

A horse whose price lengthens (drifts out) before the off as support fades. A drift can mean the market has cooled on it, though it is not a reliable signal on its own.

The numbered starting stall a horse breaks from in a Flat race; stall one is usually nearest the inside rail. The draw does not apply to jumps racing, which has no stalls.

A course-and-distance quirk where certain stalls win more often than chance, usually because of the first bend or faster ground on one side. Real at a handful of tracks, and quickly priced in by the market where it exists.

When two or more horses cannot be separated for a placing even on the photo. The stake is split by the number tied, so a two-way dead heat for the win pays out on half your stake.

A bet consisting of two equal parts: a win bet and a place bet. If the horse wins, both parts pay out. If the horse places (finishes in the designated places), only the place part pays. The place terms vary depending on the number of runners and the type of race.

The Tote's forecast: the first two home in the correct order, paid at the Tote pool dividend rather than fixed odds.

Even money, written 1/1 or evs: you win the same as your stake. £10 at evens returns £20 (£10 profit plus your tenner).

A betting exchange (such as Betfair) where punters bet against each other rather than a bookmaker, backing and laying at prices they set, with a commission charged on net winnings.

A horse's recent racing history, typically shown as a sequence of finishing positions. Form is the most studied factor in horse racing betting. A horse showing '112' has won its last race, finished second in the one before, and won the race before that (read right to left).

An accumulator of four selections; all four must win for it to pay. Multiplies four sets of odds together, and the bookmaker's margin with them.

Pick the first two horses home in the correct order. Settled at the Computer Straight Forecast (CSF) dividend rather than fixed odds, so you don't know the exact return until the result.

The traditional UK way of writing odds, like 5/1 or 7/2. The first number is the profit, the second the stake: 5/1 returns £5 profit for every £1, plus your stake back.

The long-standing market pattern where big-priced outsiders are worse value than short-priced favourites, because punters over-bet longshots chasing the payout. So backing big prices loses even more than the odds suggest.

The horse at the shortest price in a race, the one the market rates most likely to win. Favourites win the largest share of races, but the short price and the margin mean backing them every time still loses over the long run.

A bookmaker token that pays out winnings but not the stake ('stake not returned'). A £10 free bet at evens returns £10, not £20, so it is worth less than £10 in cash.

A unit of racing distance: one eighth of a mile, or 220 yards. Race distances are given in miles and furlongs, so 'a mile and a half' is twelve furlongs.

The condition of the ground on which a race is run. In the UK, going ranges from 'Firm' (hard, dry ground) through 'Good' and 'Soft' to 'Heavy' (very wet, testing ground). Some horses perform significantly better on certain types of going.

The biggest common full-cover multiple: eight selections in 247 bets, doubles up to the eight-fold, no singles. A huge outlay for a payout you are very unlikely to collect.

A horse backed so heavily its price collapses. If it wins the stable is said to have 'landed a gamble'; the ones that don't rarely make the headlines.

The tiers of top Flat racing, from Group 1 (the very best, like the Derby) down through Group 2 and Group 3 to Listed races. Together they are known as Pattern races.

A race in which horses carry different weights, allocated by the official handicapper based on their assessed ability. The aim is to give every horse a theoretically equal chance of winning. Better horses carry more weight to level the playing field.

Six selections in 57 bets, named after the '57 varieties'. Doubles up to the six-fold, no singles. Every added selection multiplies the bookmaker's margin again, so the more legs you stack the harder the whole slip has to work just to break even.

Betting after the race has started, with the prices changing live as the race unfolds. Also called in-running.

The Tote pool that needs you to find the winner of all six nominated races at a meeting. Rarely landed, so it often rolls over.

When two or more horses share the shortest price in a race, the market can't separate them.

Four selections combined into 15 bets: 4 singles, 6 doubles, 4 trebles and one four-fold. One winner returns something, all four is the big payout. Bookmakers push it hard because you pay their margin on all fifteen bets at once, which is why it is a steady loser over time.

Five selections in 31 bets: 5 singles, 10 doubles, 10 trebles, 5 four-folds and one five-fold. A bigger Lucky 15 with an extra selection, and an extra layer of the bookmaker's margin.

Six selections in 63 bets, from 6 singles up to one six-fold. The full-cover multiple with singles; the returns look large because collecting them all is so unlikely.

To bet on something NOT to happen, taking the bookmaker's side of the bet on an exchange. If you lay a horse and it loses, you keep the backer's stake; if it wins, you pay out.

Another name for the overround: the cut the bookmaker bakes into the prices so the odds add up to more than 100%. It is why the average bet loses before luck even comes into it.

A horse that has never won a race, or a race restricted to such horses. A maiden win is a horse getting off the mark for the first time.

The code of racing that includes hurdles and steeplechases — races where horses jump over obstacles. Also known as 'jump racing'. The National Hunt season traditionally runs from October to April, though there are summer jumping fixtures too.

A tipster's most confident selection of the day. The term comes from the card game Napoleon. When a racing journalist or tipster gives their 'nap', it's the horse they believe has the best chance of winning that day.

A horse that is declared but withdrawn before the race. Win singles on it are voided and the stake returned; in multiples the leg is simply removed and the rest of the bet runs.

A tipster's second-strongest selection of the day, after the nap. 'NB' stands for next best.

In jumps racing, a horse in its first season over hurdles or fences, or a race for them. Novice form can be hard to read because the horses are still learning the job.

A handicap for two-year-olds on the Flat. The young age and limited form make nurseries notoriously tricky to weigh up.

A price shorter than evens, where you stake more than you stand to win (e.g. 4/6 returns £4 profit on a £6 stake). Odds-on runners win often, but the short price means each winner pays little.

Any price longer than evens, where the profit is bigger than the stake (e.g. 3/1). The opposite of odds-on.

The bookmaker's built-in margin. Add up the chances implied by every price in a race and a fair book would total 100%; a real book totals more, and that extra slice is the house edge you pay on every bet. It grows with field size.

A runner at a very long price, sometimes called a rag or a longshot, that the market gives almost no chance. The rare big-priced winner never quite covers the long run of losers in between.

A formal complaint by a jockey or official, often about interference, that the stewards consider and which can lead to a placing being reversed.

A bet on a horse finishing in one of the designated places in a race, rather than necessarily winning. The number of places varies: typically 1st-2nd in races with 5-7 runners, 1st-3rd in races with 8-15 runners, and 1st-4th in handicaps with 16+ runners.

Three selections in 7 bets: 3 singles, 3 doubles and one treble. A Trixie with singles added, so one winner already returns something.

The Tote's most popular pool: pick a horse to be placed in each of the first six races at a meeting. One unplaced leg and the ticket is gone, which is why a big placepot pays well.

When horses cross the line too close to separate by eye and the judge calls for a photograph to decide the placings.

A smaller Tote pool than the placepot: a placed horse in races three to six of a meeting. A cheaper way into pool betting.

Two selections to finish first and second in either order. It is two forecast bets, so it costs double a straight forecast.

A deduction from your winnings when a horse is withdrawn after you bet but before the off, because the other prices were too generous once it left. The shorter the withdrawn horse, the bigger the deduction (in pence per pound).

The listing for a race showing the runners, jockeys, weights, draw and recent form. The starting point for reading any race.

The official odds of a horse at the moment the race begins, as determined by on-course bookmakers. If you don't take a fixed price, your bet will be settled at SP. The Starting Price is the benchmark against which all other prices are measured.

A jump race in which horses navigate larger, more testing fences than in hurdle races. Steeplechases include famous obstacles like open ditches and water jumps. The Cheltenham Gold Cup and Grand National are the most famous steeplechases.

Also called a Canadian: five selections in 26 bets (doubles up to the five-fold, no singles). At least two must win to return anything.

Seven selections in 120 bets (doubles up to the seven-fold, no singles). A large full-cover multiple for seven fancies.

A bet on one selection to win (or to place). The simplest bet, and the building block every multiple is made from.

A Saturday Tote pool on six televised races, with a win fund, a place fund and a rolling bonus that can build into a very large jackpot.

A horse whose price shortens on heavy support before the off. Often described as 'well backed', but a short price already has the money in it.

The horse with the next-shortest price after the favourite. A common 'value' pick, though it carries the same margin and steps out to a slightly worse price, not a better one.

The amount of money you put on a bet. Level stakes means the same amount on every bet, the fairest way to measure whether a method actually makes money.

An official review of a race, usually for interference, that can change the finishing order after the horses have passed the post. Bets are settled on the amended result.

The registered coloured jacket and cap an owner's horses race in, also called colours. They make each runner identifiable during the race.

A bet on three selections in different events. All three must win for the bet to pay out. Like a double, the returns from each selection roll onto the next, creating potentially large returns from a modest stake.

A combination bet consisting of four bets on three selections: three doubles and one treble. At least two selections must win for any return. It offers protection compared to a treble as you can still profit if only two of three selections win.

Pick the first three home in the exact order. The prices are big because getting three horses in the right order is hard; most tricasts lose.

Pool (pari-mutuel) betting: every stake goes into a shared pool, a deduction is taken, and the winners split what is left. You don't know the price until the pool closes at the off.

A bet where the odds on offer are bigger than the horse's true chance of winning. Finding genuine value over time is the only way to beat the margin, and it is very hard, because the market is a sharp forecaster.

A bet that is cancelled with your stake returned, for example on a non-runner or an abandoned meeting. No win, no loss.

Four selections in 11 bets: 6 doubles, 4 trebles and one four-fold, with no singles. At least two of your four must win to get any return. The lack of singles makes it cheaper than a Lucky 15 but harder to see a penny back.