CMS
A content management system is a piece of software or a Web based application that allows less or not technical at all people to create, modifiy or administer Web base content. Most of the CMSs are distributed under a free license. Depiste that, some are commercial solutions and target more specialized areas of expertise, or offer some other added value. However, the main goal stays the same: simplify the process of editing Web content for non technical users.
CMSs come with some fonctionalities out of the box, and those are usually augmented by a systeme of add-ons (plugins) that may be activated on demand. The more widely a CMS is used usually means that a wider variety of add-ons are also available for it. That being said, some technical knowledge may be required to update the CMS itself, or to apply the proper security patches as new security holes are discovered and as new features are requested by the users. Even the add-ons themselves may be tricky to update depending on their level of compatibility with the newest versions of the CMS itself, and with regards to other add-ons that they may depend on.
Some may claim that the features offered by the CMSs are often limited or not performant enough despite enabling a caching system. It might be preferable to use a framework instead of a CMS in that case, in order to fit the users needs more precisely. Those frameworks will without a doubt require to intervention of a developer, which defeats the purpose of a CMS: simplicity.
CMSs are often seen as a solution from another era, deprecated, and replaced by social media. However, there might still be some people interested in publishing blogs, news articles, or corporate content, where CMSs can still be useful.
Here are a few examples of CMSs I used to work with: