CMS What is it?

This definition of CMS is from the Webopedia website, they sum it up perfectly.

Abbreviated as CMS, a Content Management System, also called a Web management system is software or a group or suite of applications and tools that enable an organization to seamlessly create, edit, review and publish electronic text. Many content management systems offer a Web-based GUI, enabling publishers to access the CMS online using only a Web browser. Also, a CMS designed for Web publishing will provide options and features to index and search documents and also specify keywords and other metadata for search engine crawlers.