CMS stands for Content Management System and denotes a computer application, through which the user can easily manage, modify and create content using an easy to use interface.
A CMS allows inexperienced users to manage web pages – add and remove content, delete and create pages. Those CMSes that are designed to make it easier to manage a web page are often called WCMS which stands for Web Content Management System, however, they are almost always referred to as CMS.
In a CMS, you can embed videos and photos, graphics, text and so on.
It consists of two major elements – the Content Management Application and the Content Delivery Application. The first allows the user to manage the website's content, without the need of an experienced webmaster, and without the need for any HTML knowledge. The second one uses this information to update the site.
Some of the most popular CMSes today are WordPress; Joomla; Drupal. ETNHost gives its clients easy access to those and over 400 more CMSes.