Router In Joomla, a program that associates a path (URL) with internal Joomla queries. Normally a router contains two methods, build() and parse(). The build() method takes an array of commands and returns a JURI object. The parse() method reverses this and turns a JURI object into an array of commands.
Publisher A user level on a Joomla site with access only to the front end. Publishers have permission to write, edit, and publish site content.
Module Position Module positions are placeholders in a template. They identify positions within the template and tell the Joomla! application where to place output from modules assigned to a particular position. The template designer has complete control over module positions, creating variations between templates and the respective Joomla! default positions assigned to modules in the installation sample data. For example, the module position Left could be defined to be on the left side of the template to display a site navigation menu. So if a module is assigned the Left position, it will be displayed wherever the designer puts that Left module position - not necessarily the left side of the page. Reference: http://docs.joomla.org/Glossary