Content Management System, pronounced "CMS", is a generic term for all types of system to manage some kind of content. If you think this sounds loose and fluffy, it is. Debate continues on what a CMS really is. Attempts to diversify the term into Web Content managemt (WCMS) and Enterprise Content Managent (ECMS) has just added to the confusion.
There is a generic CMS Wiki at http://www.cmswiki.com/tiki-index.php
There is a Content Management Frameworks/Systems Overview at OSCOM, containing a list of open-source CMFs? and CMSs?.
Zope is a good platform to build a CMS on, and several have been built, mostly on top of the CMF (Content Management Framework).