A trance like study technique that can be done without looking at the studying materials. Going over and re-enforcing facts and equations in your head. Bassicly an excuse to study and be lazy in the process.
Guy: Hey dude, lets play videogames?
Me: Naw, I'm set.. I'll just sit here and compile for a bit.
To convert programming language code to executable code. Basically translating user-friendly code into code that your computer understands. Usually done by compiler programs.
For example, when programming, to make an executable program of your code, you need to compile it first.