blackjack

American  

[blak-jak] / ˈblækˌdʒæk /

noun

1. Cards.

   1. Also called twenty-one.  a gambling game in which the object is to obtain from the dealer cards whose values add up to, or close to, 21 but do not exceed it.

   2. a variety of this game in which any player can become dealer.

   3. Also called natural.  (in the game of blackjack) an ace together with a ten or a face card as the first two cards dealt.

2. a short, leather-covered club, consisting of a heavy head on a flexible handle, used as a weapon.

3. black flag.

4. a small oak, Quercus marilandica, of the eastern United States, having a nearly black bark and a wood of little value except for fuel.

5. a large drinking cup or jug for beer, ale, etc., originally made of leather coated externally with tar.

6. caramel or burnt sugar for coloring spirits, vinegar, coffee, etc.

7. Mineralogy. a dark, iron-rich variety of sphalerite.

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verb (used with object)

1. to strike or beat with a blackjack.

2. to compel by threat.

blackjack ¹ British  

/ ˈblækˌdʒæk /

noun

1. a truncheon of leather-covered lead with a flexible shaft

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verb

1. (tr) to hit with or as if with a blackjack

2. (tr) to compel (a person) by threats

blackjack ² British  

/ ˈblækˌdʒæk /

noun

1. pontoon or any of various similar card games

2. the ace of spades

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blackjack ³ British  

/ ˈblækˌdʒæk /

noun

1. a dark iron-rich variety of the mineral sphalerite

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blackjack ⁴ British  

/ ˈblækˌdʒæk /

noun

1. Also called: blackjack oak.  a small oak tree, Quercus marilandica , of the southeastern US, with blackish bark and fan-shaped leaves

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blackjack ⁵ British  

/ ˈblækˌdʒæk /

noun

1. a tarred leather tankard or jug

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Etymology

Origin of blackjack

First recorded in 1505–15; black + jack ¹

Example Sentences

The chief executive of one of the world’s largest airlines was told that he was welcome to spend his money on poker or any other casino game—but not blackjack.

From The Wall Street Journal • Apr. 25, 2026

The bill also seeks to prohibit “casino-style games” from being listed on the platforms, such as slot machine games, video poker, blackjack and bingo.

From The Wall Street Journal • Mar. 23, 2026

As California is set to ban blackjack, Los Angeles’s card clubs and cities that depend on gambling revenue are trying to stop the change.

From Los Angeles Times • Feb. 18, 2026

California’s Office of Administrative Law has greenlighted new rules that would ban card rooms from offering blackjack in April.

From Los Angeles Times • Feb. 18, 2026

Conditional probability also explains why blackjack is the only casino game of chance in which it makes sense to keep track of past occurrences.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos