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.

    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.

    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