=Acheron.= A small stream in ancient Bruttium. In 330 B.C., Alexander, king of Epirus, was killed while crossing it. =Acinaces.= A short sword used by the Persians. =Aclides.= In Roman antiquity, a kind of missile weapon with a thong fixed to it whereby it might be drawn back again. =Acoluthi.= In military antiquity, was a title given in the Grecian empire to the captain or commander of the body-guards appointed for the security of the emperor’s palace. =Aconite.= A poisonous plant. Several ancient races poisoned their arrows with an extract from this plant. =Acontium.= In Grecian antiquity, a kind of dart or javelin resembling the Roman _spiculum_. =Acquereaux= (_Fr._). A machine of war, which was used in the Middle Ages to throw stones. =Acqui.= A walled town of the Sardinian states on the river Bormida in the division of Alessandria. It was taken by the Spaniards in 1745, retaken by the Piedmontese in 1746; it was dismantled by the French, who defeated the Austrians and Piedmontese here in 1794. =Acquit.= To release or set free from an obligation, accusation, guilt, censure, suspicion, or whatever devolves upon a person as a charge or duty; as, the court acquits the accused. This word has also the reflexive signification of “to bear, or conduct one’s self;” as, the soldier acquitted himself well in battle. =Acquittance Roll.= In the British service, a roll containing the names of the men of each troop or company or regiment, showing the debts and credits, with the signature of each man, and certificate of the officer commanding it. =Acre=, or =St. Jean d’Acre=. A seaport town of Palestine (in ancient times the celebrated city of Ptolemais), which was the scene of many sieges. It was last stormed and taken by the British in 1840. Acre was gallantly defended by Djezzar Pacha against Bonaparte in July, 1798, till relieved by Sir Smith, who resisted twelve attempts by the French, between March 16 and May 20, 1799. =Acre=, or =Acre-fight=. An old duel fought by warriors between the frontiers of England and Scotland, with sword and lance. This dueling was also called _camp-fight_. =Acrobalistes= (_Fr._). A name given by the ancients to warlike races, such as the Parthians and Armenians, who shot arrows from a long distance. =Acropolis.= In ancient Greece, the name given to the citadel or fortress of a city, usually built on the summit of a hill. The most celebrated was that of Athens, remains of which still exist. =Acs.= A village in Hungary on the right bank of the Danube, noted as the scene of several battles in the Hungarian revolution, that of August 3, 1849, being the most important. =Acting Assistant Surgeons.= See SURGEONS, ACTING ASSISTANT. =Action.= An engagement between two armies, or bodies of troops. The word is likewise used to signify some memorable act done by an officer, soldier, detachment, or party.