I can't figure out the difference/relationship between menus and menus
hook_menu : Is used to define a path in Drupal. It also says what should be present in that path, who should have access to it and so.

Documentation of hook_menu

Menus : Is a list of links that fall under a category. For example Admin Menu(Admin Links), User Menu(Account, Logout) and Primary Menu(Home, Contact and so on)

Documentation of Menus