What is drill down navigation?
Allows users to progressively descend 'down' branches of a hierarchical tree into a child screen to drill down into more granular details. Drill Down Navigation allows for a consistent and focused experience that helps eliminate cognitive overload.
What is a drill down menu?
Drill down menus offer a multi-level tree structure for the user to select the metadata value from. When a user makes a selection at the first level, a second level of choices will appear that are related to the choice at the first level and so on up to eight levels deep.