Components are the most important extensions for a Joomla site, the others being modules, plugins, templates, and languages. We will go into more detail on each of these in dedicated chapters. The component menu is where you can administrate the functionality of components that are part of the Joomla core and ones you have installed.

Let's see what the extensions site (http://extensions.joomla.org/content/view/15/63/1/7/) says about the difference between components, modules, plugins, templates, and languages: