What are the main differences between application and systems software?

I may not be completely right. But I think I must share my point of view with you. With respect to my knowledge, a system software is a software that is essential for the system to operate. Consider the example of an operating system. All operating systems are system softwares. Like, Windows 98/2000/XP/Vista, Solaris, Unix, Linux and others. Without system softwares a system cannot boot. These all are system softwares. Now coming to the allpication softwares. Application softwares can be considered as the utilities for the system software. Like, to have MS-Office is not essential for the booting process of the system. Similarly different games and other such softwares. These all are Application softwares. I think, you understand.