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

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.

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.