Noun
A secret advantage; a trick not revealed until it is used.
ADDITIONAL INFORMATION: While it derives from poker, this expression is used more generally. If used to describe a specific poker hand, it is typically applied in a literal sense as in definition one.
EXAMPLE: "A concert my friend and I wanted to go to was sold out. It looked like we were really out of luck, but my friend had an ace in the hole and managed to pull through with a pair of tickets."
APPLIES TO: Online and Land-based Venues