WHAT IS IT? - the fact of a person or vehicle, etc. leaving somewhere.

WHAT IS IT? - a boat or ship for taking passengers and often vehicles across an area of water, especially as a regular service.

WHAT IS IT? - a person who is traveling in a vehicle but is not driving it, flying it, or working on it.

WHAT IS IT? - a line of people, usually standing or in cars, waiting for something, or a lot of people who want something.

WHAT IS IT? - a long passage under or through the ground, especially one made by people.

WHAT IS IT? - to go across from one side of something to the other.

WHAT IS IT? - a town by the sea or by a river that has a harbor, or the harbor itself.

WHAT IS IT? - suitable for your purposes and needs and causing the least difficulty.

WHAT IS IT? - to arrive at a place, especially after spending a long time or a lot of effort traveling.

WHAT IS IT? - protection of a person, building, organization, or country against threats such as crime or attacks by foreign countries.

WHAT IS IT? - to travel or be able to travel on an aircraft, train, bus, etc.

WHAT IS IT? - happening at a later time than expected, or happening some time after the event that caused it.

WHAT IS IT? - to show your ticket at an airport so that you can be told where you will be sitting and so that your bags can be put on the aircraft.