The ambulance that races to carry emergency patients hides the word "walk" at the root of its name. The Latin ambulare means precisely "to walk, to go about." In the 18th-century French army there were field hospitals that moved along with the battlefield, and these were called "walking hospitals" (hôpital ambulant) — the idea being that the hospital would go straight to where the wounded lay. Over time the long phrase shrank until only ambulance remained, and through the 19th-century Crimean War its meaning shifted from the hospital itself to the cart that carried the wounded. And so the idea of a "moving hospital" became the ambulance we know today.