Casino terms, defined
The floor has a vocabulary, and most of it is designed to be reassuring rather than clear. Here is what the words actually mean, with the numbers attached. Nothing here helps you win — there is no such thing. It helps you understand what is happening to your money.
- House edge
- The share of every bet a casino keeps on average over the long run, built into the rules of the game rather than taken as a fee. Blackjack with perfect basic strategy is about 0.5%; baccarat banker about 1.06%; single-zero roulette 2.70%; double-zero roulette 5.26%. The edge never stops applying, and no betting pattern removes it.
- Return to playerRTP
- The percentage of everything wagered that a machine pays back to players across its lifetime — typically 88–96% on slots. It is not a refund on your session. It is measured over millions of spins, and it applies to money cycled, not money brought: winnings you re-bet are exposed to the edge again.
- Average Daily TheoreticalADT
- What a casino expects to win from you per day of play, calculated as average bet × hours played × decisions per hour × house edge. It is the number your comps are priced from. Crucially it is theoretical — the casino rates you on your exposure, not on whether you actually won or lost that day.
- Comp
- Short for complimentary — rooms, meals, drinks, show tickets, rebates or discretionary extras given back to a player based on their tracked play. Comps are a marketing rebate funded by your theoretical loss, typically returned at a fraction of it. They are earned by exposure to the edge, not by losing.
- Virtual reel
- A software list inside a slot machine, often hundreds of entries long, that maps onto the physical reel positions you can see. Because many list entries can point at one position and only a few at another, two symbols that look equally likely on the glass can differ enormously in probability. Patented in 1984 and near-universal since.
- Near-miss
- A displayed outcome that stops just short of a win — the jackpot symbol landing one position off the payline. Because virtual reels let designers weight the positions adjacent to a jackpot far more heavily than the jackpot itself, near-misses can be made to appear far more often than the underlying odds suggest. A near-miss is mathematically identical to any other loss.
- Loss disguised as a winLDW
- On a multi-line machine, an outcome that triggers celebratory sound and animation while returning less than the amount staked — betting 50 cents across twenty lines and collecting 20 cents back. The spin registers to the player as a win. It is a 30-cent loss.
- Time on device
- The total time a player spends actively wagering. Because the house edge applies to every bet resolved, expected loss scales with the number of decisions, not the size of the bankroll brought. This is why casino floors are engineered to remove clocks, windows and straight exits: duration is the product.
- Basic strategy
- The mathematically optimal decision for every blackjack hand against every dealer upcard, derived by computing the expected value of each option. Playing it perfectly reduces the house edge to roughly 0.5% under common rules. It minimises the edge; it does not reverse it.
- Card counting
- Tracking the ratio of high to low cards remaining in a blackjack shoe to identify when the composition briefly favours the player. It is mathematically real and it is not illegal, but continuous shuffling machines, multi-deck shoes, unfavourable rules and casino counter-measures make it impractical for almost everyone. Casinos may refuse service to suspected counters.
- Back-off
- When a casino ends a player's action without ejecting them — typically an invitation to play any game except the one they were winning at, or a request to flat-bet. It is a private business decision requiring no stated reason, and it is the standard response to a player the house believes has an edge.
- Rolling programme
- A VIP arrangement where a player buys non-negotiable chips and is paid a commission on the total volume rolled rather than on the outcome. It prices the player by turnover, which means the programme's value to the casino rises with how much is wagered, independent of who wins any individual hand.
- Junket
- An intermediary that brings players to a casino, often extending credit and collecting a commission on their rolling volume or losses. The junket's revenue is tied to how much its players wager, which places its commercial interest structurally opposite to the player's.
- Variance
- The natural swing of results around the expected value. High variance is why a player can win over a night, a weekend, even a season, while the underlying edge is unchanged. Short-run results say nothing about whether a game is beatable; they only say the sample was small.
- Gambler's fallacy
- The belief that an independent random event is 'due' because of what came before — that red is likely after a run of black, or a machine must pay soon. Each spin, hand and shoe outcome is independent. The device has no memory of previous results and no obligation to balance them.
- VigorishCommission, juice
- A commission the house takes on a winning bet, most familiarly the 5% charged on winning banker bets in baccarat. It exists precisely because that bet would otherwise favour the player; the commission is what restores the house's margin.
Every game ranked by house edge, on one page: get the free cheat sheet. The full treatment is in The Upper Hand.
Consumer education, not gambling or financial advice. If gambling is causing you or your family harm: National Council on Problem Gambling (SG) 1800-6-668-668 · ncpg.org.sg