Holdout (gambling)
（重定向自Holdout device）
In gambling jargon, a holdout is any of numerous accessories used by cheats to help them "hold-out" a card (or cards) during a card game. Some holdout devices are extremely simple and require moderate or advanced manipulative skill to be used properly. On the other hand, there is a group of holdout devices which are mechanical in nature, therefore they fall under a separate category of holdout machines. Even if those machines are complex mechanical apparatuses, they still require a good level of skill from the cheat's part, to be used well.