A particular army can be named or numbered to distinguish it from military land forces in general. For example, the First United States Army and the Army of Northern Virginia. In the British Army and United States Army, it is normal to spell out the ordinal number of an army (e.g. First Army), whereas corps use Roman numerals (e.g. III Corps) and lower formations use figures (e.g. 1st Division).
In the Soviet Red Army and the Soviet Air Force, "Armies" were actually corps-sized formations, subordinate to an Army Group-sized "front" in wartime. In peacetime, a Soviet army was usually subordinate to a military district.
The distinguishing flag of a United States army is bicoloured, white over red, measuring 91.4 centemetres (36 inches) hoist by 121.9 centemetres (48 inches) fly, with gold fringe. In the center is a rendering of the army's shoulder-sleeve insignia, measuring 38.1 centemetres (15 inches) in height.
For the hierarchy of land forces organizations, see military organization.