I have heard about things like \"C Runtime\", \"Visual C++ 2008 Runtime\", \".NET Common Language Runtime\", etc.
Run time exactly where your code comes into life and you can see lot of important thing your code do.
Runtime has a responsibility of allocating memory , freeing memory , using operating system's sub system like (File Services, IO Services.. Network Services etc.)
Your code will be called "WORKING IN THEORY" until you practically run your code. and Runtime is a friend which helps in achiving this.