Anything that indicates future trends.
A stock or bond that is widely believed to be an indicator of the overall market's condition.
The leading sheep of a flock, having a bell hung round its neck.
A sea explorer.
A device that navigates an aircraft, automobile or missile.
A person who navigates, especially an officer with that responsibility on a ship or an aircrew member with that responsibility on an aircraft.
A user interface that allows navigating through a structure of any kind.