For a while I have been curious about the etymology of the English word 'ambulance' since it seems to be derived from the Latin word 'ambulare' (to walk). This seems a strange origin for the word. People who require medical attention are generally unable to move, much less walk. How did this word end up having the meaning it possesses?
So it might be related to the fact that ambulances were going around by walking (of horses).
It seems, however, that the word enter into English from French (which itself comes from Latin) in the XIX century. At least that's what the Concise Oxford Dictionary of English Etymology says (here, although paywalled):
moving hospital accompanying an army; vehicle to convey injured. XIX. — F. ambulance, repl. hôpital ambulant ‘walking hospital’, earlier hôpital ambulatoire; F. ambulant — prp. of L. ambulāre walk
More about the French word ambulance can be found here.