Forum Moderators: phranque
CMS = Content Management System
For me it means a system that records, holds and displays content. You can add/edit content, display it in various formats (for example html vs. pdf vs. rss) and usually manage the content of a website with a CMS.
A fairly simple definition, but a good start (IMO!), as the CMS' that are available these days do way more than just manage content.
Some definitions, or better, some of the feature lists of more popular CMS' go way beyond management of content, getting into actual site building, adding of modules like polls, newsletter sign-ups etc. (for example Drupal). These apps, IMO, are more like site builders with a CMS as a component.
CMS does not mean site creation but site content management.