(1)〈美〉黑杰克棒
一种装有弹性手柄，包有皮革，皮革上缀有铅块或其它金属的短大头棒，为罪犯常用的伤人武器，有时警察也用。

(2)黑杰克牌戏
也称21点〔vingt-et-un〕。通常用于赌博。

• open court
• open cover
• open credit
• open danger
• open doors
• open-end
• open-end contract
• open-end credit plan
• open-end investment company
• open-end investment trust
• open-end lease
• open-end mortgage
• open-end settlement
• open-end transaction
• open entry
• open fee
• open fields doctrine
• open hearing
• opening
• opening a credit
• opening statement
• opening the case
• opening the pleadings
• open law
• open letter of credit