A menu is a named tree of navigation links your storefront theme renders — a header menu, a footer menu, a sidebar of categories. Every store starts with a Main Menu, and you can add more up to your store's menu limit.
Names and handles
A menu has a display name and a handle — the short lowercase identifier your theme uses to pick which menu to render where. When you create a menu the handle is generated from the name automatically (and made unique if it collides); if you type one yourself it must be lowercase words joined by hyphens, and a handle another menu already uses is rejected.
Items and nesting
Each item in a menu has a title, a link, and an optional set of child items — a dropdown. Items nest up to the platform depth limit, and each level keeps its own order. A menu also has caps on the total number of items and on how many items may share one parent; the editor shows the limits as you approach them.