In Joomla!, a Menu is a set of menu items used for website navigation. Each menu item defines an URL to a page on your site, and settings that control the contents(articles, category(ies) lists, tagged items, etc.) and style(module(s), layout) of that page.
In Joomla!, a Menu is a set of menu items used to create the website's navigation structure. Each menu item defines an URL to a page on your site, and it holds settings that control the content display of that page. Creating menus is rather simple. With a new menu in place, you can start creating pages for the website, directly accessible from the navigation menu, by adding new menu items in the menu. A website can have more than 1 menu.
A Menu isn't automatically shown on the site's front-end. In order to display a menu, you need to create a Menu Module using the module manager and instruct the module about which Menu to show. Subsequently, you can select where the module should appear on the site, by choosing one of the available module positions of the active template, as well as, you have the option to display the menu in all, or some of the pages of the website.
Each menu can be shown by one or more modules (making it possible to show the same menu in different positions). It is also possible to create Split menus.
A Menu that isn't shown by any module is commonly called a hidden menu. Hidden menus can be used to create URLs that are not visible on any page.