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 a large drinking cup or jug for beer, ale, etc., originally made of leather coated externally with tar.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

E-tabs grew out of decades-old “charitable gaming” laws that permitted smaller games like bingo and blackjack.

From The Wall Street Journal • Apr. 7, 2026

Two southeast Los Angeles cities proposed a sales tax increase to offset the financial impact of California’s blackjack ban, which officials said would devastate their local economies.

From Los Angeles Times • Mar. 27, 2026

Authorities want to close a legal loophole that allowed card clubs to offer blackjack and other banked games in which players play against the house.

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