Suites are collections of related scripts attached to one or more private menus.
The subject is discussed in greater detail in Chapter 10 of the Tutorial. It explains this menu and its use in a dialog. Minimal Menus, or Command-minus, is quite useful. When you've finished using a suite, you can use this menu option to remove its menu from the menubar. The UserLand Suites sub-menu contains suites that are included with Frontier.