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ARMY

Capitalize when preceded by the name of a country (as long as army is part of the official name) or when the name is well established:
            United States Army                British Eighth Army
            Russian Army                           Red Army
            People's Liberation Army
            Iraqi Army
but     Israeli army, Japanese army (army is descriptive in these instances, not the official name)

When army is used by itself, capitalize in references to the U.S. Army, but lowercase such references to any foreign army.

Spell out units through Tenth.
            United States Army, the Army, Army officer
             the 19th Army, the army
             the Indian Army, the army, army officer
             Red Army, the army
             Union Army, Grant's army, Confederate Army
             Army of the Potomac, the army

For Army ranks and abbreviations see MILITARY RANKS.

See also:      AIR FORCE, COAST GUARD, MARINE CORPS, NAVY
                        armed forces, armed services, special forces
                        MILITARY UNITS
                        Ranger, Rangers, SEAL, SEALs
                       TITLES OF PERSONS.