The word 'ambulance' derives from the
Latin 'ambulare', meaning 'to walk or move about'. This gave rise to
the French hôpital (sic) ambulant, meaning mobile hospital. It used
to refer to a temporary medical structure that could be easily
moved, such as movable army medical hospitals. In English, ambulance
first appeared around 1798 and also referred to temporary hospital
structures.
Ambulances were first used for emergency transport in 1487 by the
Spanish, and civilian variants were put into operation in the 1830s.
Mobile medical transport vehicles were also called ambulances in
French and were designed to get injured soldiers off the battlefield
and to medical aid during battle. One of the first instances of this
was during the Crimean War. During the American Civil War they were
known as ambulance wagons.
The first known hospital-based ambulance service was based out of
Commercial Hospital, Cincinnati, Ohio, US, in 1865.