ace in the hole

American  

noun

1. Poker. an ace dealt and held face down, especially in stud poker.

2. an advantage or a resource kept back until the proper opportunity presents itself.

   His ace in the hole is his political influence.

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ace in the hole Cultural  

1. A hidden advantage or resource kept in reserve until needed: “The coach was certain that his new trick play would turn out to be his ace in the hole.” This term comes from the game of stud poker, in which one or more cards are turned face down, or “in the hole,” as bets are placed. The ace is the card with the highest value.

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ace in the hole Idioms  

1. A hidden advantage or resource kept in reserve until needed, as in The prosecutor had an ace in the hole: an eyewitness. The term comes from stud poker, where each player is dealt one card face down—the so-called hole card—and the rest face up. Should the hole card be an ace, the player has a hidden advantage. Hole here simply means “a hiding place.” In the 19th-century American West, the expression was used to refer to a hidden weapon, such as a gun concealed in a shoulder holster. By the 1920s it had become a metaphor for any surprise advantage or leverage.

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Etymology

Origin of ace in the hole

An Americanism dating back to 1920–25

Example Sentences

But make no mistake, all of this is enabled by low costs to reach space, and SpaceX’s ace in the hole is its giant, fully reusable rocket, Starship.

From Barron's • Apr. 26, 2026

Although Johnston came off the bench, he was an ace in the hole whenever the Panthers needed one.

From The Wall Street Journal • Mar. 20, 2026

When it’s all said and done, and the headphones have lost their charge, there’s nothing more for “Undertone” to do, no ace in the hole final punch to leave viewers breathless.

From Salon • Mar. 15, 2026

Putin, though, may have one ace in the hole.

From Seattle Times • Dec. 23, 2022

But Ernest had one last ace in the hole: Alfred Loomis.

From "Big Science" by Michael Hiltzik