A navigator is a resident application, typically provided by the manufacturer, that the end user can activate at any time. The navigator can be used to select services, applications, and initiate interoperable applications.
The navigator, or five-way navigator, consists of the two large, concentric buttons in the middle of the lower part of many Palm devices. Press the edges to move up, down, right, or left, and the center button to select items. The navigator works differently in different applications, but it's usually an easy way to operate the device with one hand.