Ambulance (Lat. ambulare, to walk), a temporary and movable military hospital, formed on the field of battle for the immediate succor of the sick and wounded. The word is technically applied to covered wagons on springs, and to such other vehicles as are used for moving wounded men from the field of battle to the temporary hospitals, or for carrying the sick and wounded with the moving columns or to the permanent hospitals. The ambulance is a comparatively modern invention, due mainly to the French. Military surgery was formerly but little understood, and those who were wounded on the field of battle were left to the care of those around them, without any selection of fit persons for the duties of surgery. Nor do we find any trace of a regularly organized system of military hospitals, moving with the army, until the time of Henry IV. of France. The movable ambulances at first consisted of a cumbrous depot of surgical and medical appliances, kept with the baggage at a distance. At present two kinds of ambulances are recognized: one fixed or general, the other movable and light. The larger and reserved ambulances remain with the heavy baggage at some distance from the field of battle, and may be established either in permanent buildings or in large tents or temporary structures.

In the late war in France the temporary hospitals fitted up in the palace of Versailles and in the public buildings of Paris were called ambulances. The lighter and more strictly movable ambulances accompany the soldiers on the field. The system was brought to its highest state of efficiency in the United States army during the civil war. The surgeons accompanying the troops are supplied with abundant means, such as lint, plaster, and bandages, for dressing wounds, and with the necessary instruments for surgical operations. Ambulances, or small spring wagons drawn by one or two horses (to which the term is in the United States commonly confined), and containing all the necessary appliances, including beds, for transporting two or more patients, follow close after the troops on the march and in approaching the field of battle. The ambulances of each division or corps d'armee are organized into a corps under the command of a subaltern of the line, styled ambulance officer. Railway cars and steamboats have been provided with beds and all other conveniences for carrying sick and wounded soldiers to the permanent and more distant hospitals.

The American ambulance system, with local modifications, is now used by most civilized nations.