A mega menu is an advanced type of drop-down menu used on a website for navigation. Unlike traditional drop-down menus, which usually only contain a list of links, mega menus provide a larger, clearer structure that allows for multiple levels of sub-menus, categories and even visual elements such as images or icons to be displayed. Mega menus make it easier to navigate complex or content-rich websites by giving users quick and intuitive access to different areas of the website.