Pilot

A person who steers a ship, a helmsman.

A person who knows well the depths and currents of a harbor or coastal area, who is hired by a vessel to help navigate the harbor or coast.

A guide book for maritime navigation.

An instrument for detecting the compass error.

To control (an aircraft or watercraft).

To guide (a vessel) through coastal waters.

To test or have a preliminary trial of (an idea, a new product, etc.)

Made or used as a test or demonstration of capability.

"The pilot plant showed the need for major process changes."

Used to control or activate another device.

"a pilot light"

Being a vehicle to warn other road users of the presence of an oversize vehicle/combination.

"a pilot vehicle"