Short for Content Management System. Source of laughter and tears. Often used as a euphemism for Wordpress by clients, which, again is a euphemism for “I don’t want to pay for technology”. Using a CMS (aka Wordpress) for the wrong purpose often leads to a “CMS in a CMS.” The most common misunderstanding when it comes to CMS is that the Content Management System replaces Content Management. Systems facilitate management, they do not replace it.
The rest of iA’s dictionary is pretty fun as well.