1. 体制;组织方式;建制
    A particular set-up is a particular system or way of organizing something.

    e.g. It appears to be an idyllic domestic set-up...
           这似乎是一种田园诗般的家庭组成格局。
    e.g. I gradually got rather disillusioned with the whole setup of the university.
           渐渐地，我对大学的整个体制感到相当失望。

2. 陷害;栽赃
    If you describe a situation as a set-up, you mean that people have planned it in order to deceive you or to make it look as if you have done something wrong.

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    e.g. He was asked to pick somebody up and bring them to a party, not realizing it was a setup.
           有人让他开车去接几个人来参加聚会，他并没有意识到这是个陷阱。

3. (软件或硬件的)安装，设置
    The set-up of computer hardware or software is the process of installing it and making it ready to use.

set-up的解释

    e.g. The worst part of the set-up is the poor instruction manual...
           安装时最糟糕就是操作指南讲述不够清楚。
    e.g. ... the setup program.
           安装程序