ambul- +

(Latin: ambulare, to walk, to go)

A change from "walking" to a vehicle

How do we get from ambul, which is clearly related to the action of "walking", to the ambulance chasing down the street to administer emergency medical care?

Everyone recognizes the word ambulatory, from Latin ambulans, as meaning "capable of walking". What is confusing to some people is the name of the vehicle used to transport patients to a hospital, an ambulance, which certainly does not walk now.

In the mid-nineteenth century, the French developed an hôpital) ambulant, which referred to a mobile hospital whose personnel went out to the wounded soldiers to try to save their lives. Until the Crimean War in 1854, wounded soldiers on the battlefield received no medical attention until after it became night.

After Napoleon III entered the war, his men devised a means to serve injured soldiers more quickly; such as, an itinerant hospital or a litter that contained bandages, tourniquets, and other medical supplies which could be administered quickly on the field before the soldier was moved.

Because the litter was carried from place to place, the French called this field hospital, as indicated earlier, hôpital ambulant, "the walking hospital". The English borrowed the idea and the name; however, they dropped the first word and anglicized the second so that today the vehicle used to transport the sick or woiunded is now called an ambulance, even though neither it nor its patients are ambulatory and are certainly not ambulating.