Blackjack glossary

Every term you'll meet in our guides — and at the table — defined in plain English. Organized the way you'll learn them: the game first, then the rules, then strategy, counting, and the bankroll math.

The game & the table

Blackjack (natural): An ace plus a ten-value card as your first two cards. Pays 3:2 at a proper table and beats every other 21. If both you and the dealer have one, the hand pushes.
Hard hand: A hand with no ace, or whose ace can only count as 1 without busting. 10-7 is hard 17 — one bad draw from disaster, no cushion.
Soft hand: A hand whose ace currently counts as 11. Ace-6 is soft 17; it can't bust with one more card, which is why soft hands are played more aggressively than their totals suggest.
Stiff: A hard total of 12 through 16 — strong enough to bust if you hit, weak enough to lose if you stand. Most of the hard decisions in blackjack are stiffs.
Upcard: The dealer's face-up card, and the most important card on the table: every basic strategy decision is your hand versus this card.
Hole card: The dealer's face-down card, revealed after all players act.
Push: A tie with the dealer. Your bet is returned — nothing won, nothing lost.
Shoe: The box holding the multiple decks (usually 4–8) that cards are dealt from face up. "Shoe game" is shorthand for multi-deck blackjack.
Pitch game: A single- or double-deck game dealt by hand, cards face down. You hold your cards — with one hand only.
Cut card: The colored plastic card placed in the shoe after the shuffle. When it appears, the dealer finishes the round and reshuffles. Its position sets the penetration — a detail counters care deeply about.
Burn card: The card discarded face down off the top of a freshly shuffled shoe before dealing begins.
Discard tray: The clear plastic tray holding already-dealt cards. Counters glance at it to estimate how many decks remain for the true count conversion.
First base / third base: First base is the seat to the dealer's immediate left and acts first; third base acts last, right before the dealer. Where you sit has no effect on your odds.
Insurance: A side bet, offered when the dealer shows an ace, that the hole card is a ten. Pays 2:1 but carries a ~7.7% house edge in a fresh shoe — always decline it, unless you're counting and the count says otherwise. The insurance math →
Even money: The dealer's offer to pay your blackjack 1:1 immediately when they show an ace, rather than risk a push. It is mathematically identical to taking insurance — and just as bad a deal at a neutral count.
Toke: A tip for the dealer — a chip handed over or a small bet placed on their behalf. Customary, never required.

Rules on the felt

3:2 / 6:5: What a blackjack pays. 3:2 is the traditional, correct payout ($15 per $10 bet); 6:5 ($12 per $10) adds roughly 1.4% to the house edge and is the single worst rule in the modern game. Non-negotiable: play 3:2. How to choose a game →
H17 / S17: Whether the dealer hits (H17) or stands (S17) on soft 17. S17 is about 0.2% better for you, and the correct basic strategy differs between the two — match your chart to the felt.
DAS (double after split): Permission to double down on hands you just created by splitting a pair. Worth about 0.14% to you and assumed by most strategy charts.
Late surrender: The option to forfeit your hand and keep half your bet, after the dealer confirms no blackjack. Worth about 0.08% when offered and used correctly — mostly on hard 15s and 16s against strong upcards.
RSA (re-splitting aces): Permission to split again if you draw a third ace after splitting a pair of them. A small bonus (~0.08%) where offered; most tables give split aces one card each and no more.
CSM (continuous shuffle machine): A machine that returns discards to the shuffle after every round, keeping the shoe effectively always fresh. Roughly neutral for a basic strategy player (though it deals more hands per hour); completely unbeatable for a card counter.

Strategy fundamentals

Basic strategy: The mathematically correct action — hit, stand, double, split, or surrender — for every possible hand against every dealer upcard, assuming a neutral shoe. Cuts the house edge from 1.5–2% (typical guessing) to roughly 0.5%. The complete guide & charts →
House edge: The percentage of every bet the casino expects to keep over the long run. A 0.5% edge means an expected loss of 50 cents per $100 wagered — the standard yardstick for comparing games and rules.
Expected value (EV): The long-run average result of a decision or bet, over every way the cards can fall. The entire discipline of advantage play reduces to one instruction: always take the highest-EV action available.
Composition (of the shoe): The mix of ranks remaining in the undealt cards. Basic strategy assumes a neutral composition; card counting is the art of noticing when it stops being neutral.

Card counting

Card counting: Tracking a single number that summarizes how the remaining shoe differs from average, then betting more when the difference favors you. Legal everywhere in the US; unwelcome in casinos. How counting works, from first principles →
Hi-Lo: The standard counting system since the 1960s: 2–6 count +1, 7–9 count 0, tens and aces count −1. Captures about 97% of the available betting information with the simplest possible arithmetic.
Tag: The value a counting system assigns to a card rank (+1, 0, or −1 in Hi-Lo). Tags approximate each rank’s measured effect on your expected value.
Running count (RC): The cumulative sum of tags for every card seen since the shuffle. Rises as small cards leave the shoe (good for you), falls as big ones do.
True count (TC): The running count divided by the number of decks remaining — converting a raw surplus into a concentration. Every downstream decision (bet size, deviations) keys off the true count, and each TC point is worth roughly 0.5% of edge.
Balanced count: A system whose tags sum to exactly zero over a full deck, like Hi-Lo. A correctly kept balanced count always returns to zero at the end of the shoe — which makes practice self-checking.
Effect of removal (EoR): The measured change in player EV when one specific card is removed from the deck. Removing a 5 helps you most; removing an ace hurts most. Counting systems are linear approximations of the EoR table.
Betting correlation: How well a counting system's tags correlate with the true effect-of-removal values — the measure of its betting power. Hi-Lo's is about 0.97, which is why fancier systems buy so little.
Penetration: How much of the shoe is dealt before the reshuffle — "75% pen" means 4.5 of 6 decks. The most important property of a beatable game: high counts live deep in the shoe, and a shallow cut card never lets you reach them.
Deviation (index play): A specific spot where the true count overrides basic strategy — like standing on 16 vs 10 at any positive count. The index is the count at which the better play flips. The full deviation charts →
Illustrious 18: Don Schlesinger's list of the 18 index plays that deliver the large majority of all play-variation profit. The standard deviation syllabus, alongside the Fab 4.
Fab 4: The four late-surrender index plays that matter, companion to the Illustrious 18. Only relevant at tables offering surrender.
Spread: The ratio between your biggest and smallest bet, like 1–8 or 1–12. Since betting the count is where nearly all the money is, your spread largely determines your edge — and how much attention you attract.
Wonging (back-counting): Counting a table from behind without playing, and sitting down only when the count turns favorable. Named for Stanford Wong. Skips the negative-EV hands entirely; countered by "no mid-shoe entry" signs.
Cover: Behavior designed to make a counter look like a gambler: varied bet timing, occasional deliberately imperfect plays, chatting, drinking (or appearing to). Costs a little EV to buy longevity.
Heat: Casino attention on a suspected advantage player — the pit boss watching, the phone call upstairs, the new dealer shuffling early. The precursor to a back-off.
Back-off / barring: A back-off is the casino telling you that you may no longer play blackjack (other games usually remain fine). Barring is the formal version: being trespassed from the property. Neither is an accusation of a crime — counting is legal; casinos simply refuse the business.

Bankroll & risk

Bankroll: Money set aside exclusively for play — the fund that absorbs variance. All professional bet sizing is expressed as a fraction of bankroll, which is why the same game can be a good bet for one player and reckless for another.
Unit: Your base betting amount, the denominator of a spread. A 1–8 spread with a $15 unit means bets from $15 to $120.
Variance / standard deviation: The measure of how far short-run results swing around expectation. Blackjack runs about 1.15 standard deviations per unit per hand — which is why a player with a genuine edge can lose for weeks. The edge is small; the noise is large.
Kelly criterion: The bet-sizing formula (edge ÷ variance, as a fraction of bankroll) that maximizes long-run growth. Professionals typically bet half-Kelly, because overbetting is punished far more harshly than underbetting.
Risk of ruin (RoR): The probability of losing your entire bankroll before the long run arrives, given your game, spread, and bankroll. The number every counter should compute before playing — 5% or lower is a common professional target.
Hourly EV: Expected profit per hour: average bet × average edge × hands per hour. The honest measure of what a game is worth — and what the EV Analyzer computes for any game you give it.

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Definitions orient you; the guides teach you. Start with how blackjack worksif you're new to the game, the basic strategy guide to start playing correctly, or the card counting guidewhen you're ready to go after the edge itself.