An ambulance is a transport for transporting sick or injured people, to, from or between places of treatment for an illness or injury. The term ambulance is used to describe a vehicle used to bring medical care to patients outside of the hospital or to transport the patient to hospital for follow-up care and further testing.

The term ambulance comes from the Latin word ambulare, meaning to walk or move about which is a reference to early medical care where patients were moved by lifting or wheeling. The word originally meant a moving hospital which follows an army in its movements.

Nowadays, not only there is ‘land’ ambulance, but also emergency air ambulance
There is no difference of air ambulance from the land one. Same thing, air ambulance offers 24 hour emergency and non-emergency ambulance services throughout the world.