What is difference between static and content management system?

Static content never changes, it is just content that was placed on a website but remains the same. A Content management System is basically software that allows you to easily make changes to your website and manage content within it, such as products within an online store.

GOcms is an example of a great CMS and they have an Excellent article explaining what a content management system is as well, I've added the article as a related link.