CMS is an acronym for Content Management System.
A content management system is a platform for creating and managing content on a website, regardless of that particular site’s format or function. This helps make updating and maintaining a site easier, since every aspect of it can be handled from a single interface. Most types of CMS dramatically reduce the need for coding by hand, which further simplifies site maintenance by allowing a site to be designed and created by one party, and updated by another party that may be less proficient in coding.
Content management systems are particularly useful in situations where a consistent appearance and behavior is desired across all of the pages on a site, as with blogs, e-commerce sites, wiki pages, or news sites. They also help manage how sites interact with specific users, i.e. by delivering content translated into other languages, or converted into other currencies.