A master copy of something such as a film or a tape recording is an original copy that can be used to produce other copies.

柯林斯字典里查来的英语解释，电影或磁带就是指母带。可以用来做其他拷贝。在专业词汇里面的意思应该跟上面一样的。

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Tool that makes a master copy of your database, makes one or more remote copies of the database, and then synchronizes updates to the databases.

创建数据库的主副本、一个或多个远程副本并且保持数据库的同步更新的工具。

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A prized object in the factory is the stamper, the master copy of a software product that takes great precision to produce.

压模，软件产品的主拷贝，需要极大的精度去生产，是工厂的一件弥足珍贵的物品。

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"You can have a master copy of PC Cillin that makes sure all your copies are up to date just by clicking on one, " says Mr Craig from Trend Micro.

BBC: NEWS | Technology | Home PC face security onslaught

On Monday morning, the SDLP's Alban Maginness posed alongside other local elected representatives at the site with a giant copy of the new master-plan (a photographer captured the event but broadcasters weren't invited).

BBC: Girdwood barracks development: devil in the detail?

The master copy of the interview was lost in transit, but director Paul Sen had secretly kept a copy on VHS tape, Cringely said.

CNN: Mark Milian,