Definition: The word "mod_mainmenu.php" refers to an application or framework that provides a default main menu for a web application or website. In the context of programming, it's used in combination with "main_menu.php" (for web applications) or "side_menu.php" (for mobile apps). Specifically, it defines a PHP script that is executed by a theme or module when the page loads. This script serves as the main menu for the website and can include various sections such as categories, featured posts, links to other pages, etc.