Blackjack Glossary
Every term you will hear at a blackjack table or read on this site, in plain English. For the rules end to end, start with how to play blackjack.
- Blackjack / natural
- An ace plus a ten-value card as your first two cards. Beats any other 21 and usually pays 3:2.
- Bust
- Going over 21. An immediate loss, even if the dealer later busts too.
- Hit
- Take another card.
- Stand
- Take no more cards.
- Double down
- Double your bet, receive exactly one more card, then stand. Allowed on your first two cards.
- Split
- Turn a matching pair into two separate hands, each with its own bet equal to the original.
- Surrender
- Forfeit your hand for half your bet. 'Late' surrender (the common kind) is offered only after the dealer checks for blackjack.
- Insurance
- A side bet, offered when the dealer shows an ace, that the dealer has blackjack. Pays 2:1. A losing bet unless you're counting.
- Even money
- Taking a guaranteed 1:1 payout on your blackjack when the dealer shows an ace. Mathematically identical to insurance, and equally inadvisable.
- Upcard
- The dealer's face-up card. Half of every strategy decision.
- Hole card
- The dealer's face-down card.
- Peek
- The dealer checking the hole card for blackjack when showing an ace or ten, before players act.
- Soft hand
- A hand with an ace counting as 11 (ace-6 is soft 17). Can't bust on the next card.
- Hard hand
- A hand with no ace, or an ace forced to count as 1.
- Stiff
- A hard 12 through 16. These hands can bust on one card and beat nothing on their own.
- Push
- A tie with the dealer. Your bet is returned.
- S17 / H17
- Whether the dealer stands (S17) or hits (H17) on soft 17. H17 raises the house edge by about 0.2 percentage points.
- DAS
- Double after split. Being allowed to double down on hands made by splitting. Player-favorable.
- RSA
- Resplit aces. Being allowed to split again when a split ace draws another ace. Player-favorable.
- 6:5
- A blackjack payout of 6:5 instead of 3:2. Adds about 1.4 percentage points to the house edge, the worst common rule in the game.
- Shoe
- The box holding multiple shuffled decks, usually six or eight.
- Penetration
- How deep into the shoe the dealer deals before reshuffling. Deep penetration is what makes counting viable.
- Cut card
- The plastic card inserted into the shoe that marks the reshuffle point.
- CSM
- Continuous shuffle machine. Returns dealt cards to the shuffler constantly, which makes card counting impossible.
- House edge
- The percentage of each bet the casino keeps on average in the long run. We measured it by rule.
- Expected value (EV)
- The average result of a decision if it were repeated forever. Basic strategy is the highest-EV action in every spot.
- Basic strategy
- The complete set of highest-EV plays for every hand versus every upcard, assuming no knowledge of the remaining shoe.
- Deviation
- A departure from basic strategy justified by the count, such as standing 16 vs 10 when the true count is positive.
- Running count
- In Hi-Lo counting, the accumulated sum of card tags (+1 for 2–6, 0 for 7–9, −1 for tens and aces) seen so far.
- True count
- The running count divided by the estimated decks remaining. The number that measures your edge.
- Flat betting
- Betting the same amount every hand, regardless of the count.
- Bankroll
- The money set aside for play. Bet sizing relative to bankroll is what separates variance from ruin.
- First base / third base
- The seats immediately left and right of the dealer, first and last to act. Position doesn't change the math.
- Toke
- A tip for the dealer.