| NATO Map Symbols[1] |
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 -_Unspecified_or_Composite_All-Arms_(NATO_APP-6).svg) |
| a friendly army |
-_Unspecified_or_Composite_All-Arms_(NATO_APP-6A).svg) |
| a hostile army |
Afield army (also known asnumbered army or simplyarmy) is amilitary formation in many armed forces, composed of two or morecorps. It may be subordinate to anarmy group.Air armies are the equivalent formations inair forces, andfleets innavies. A field army is composed of 80,000 to 300,000 soldiers.
Specific field armies are usually named or numbered to distinguish them from "army" in the sense of an entire national defence force or land force. InEnglish, the typicalorthographic style for writing out the names of field armies isword numbers, such as "First Army"; whereas corps are usually distinguished byRoman numerals (e.g. I Corps) and subordinate formations withordinal numbers (e.g. 1st Division). A field army may be given a geographical name in addition to or as an alternative to a numerical name, such as theBritish Army of the Rhine,Army of the Potomac,Army of the Niemen orAegean Army (also known as the Fourth Army).
TheRoman army was among the first to feature a formal field army, in the sense of a very large,combined arms formation, namely thesacer comitatus, which may be translated literally as "sacred escort". The term is derived from their being commanded byRoman emperors (who were regarded as sacred), when they acted asfield commanders. While the Romancomitatensis (plural:comitatenses) is sometimes translated as "field army", it may also be translated as the more generic "field force" or "mobile force" (as opposed tolimitanei or garrison units).
In some armed forces, an "army" is or has been equivalent to acorps-level unit. Prior to 1945, this was the case with agun (軍; 'army') within theImperial Japanese Army, for which the formation equivalent in size to a field army was ahōmen-gun (方面軍; 'area army'). In theSoviet Red Army and theSoviet Air Forces, an army was subordinate in wartime to afront (an equivalent ofarmy group). It contained at least three to fivedivisions along with artillery, air defense, reconnaissance and other supporting units. It could be classified as either a combined arms army (CAA) or tank army (TA); and while both werecombined arms formations, the former contained a larger number ofmotorized rifle divisions while the latter contained a larger number oftank divisions.[2] In peacetime, aSoviet army was usually subordinate to amilitary district.
Modern field armies are large formations which vary significantly between armed forces in size, composition, and scope of responsibility. For instance, withinNATO a field army is composed of a headquarters, and usually controls at least two corps, beneath which are a variable number ofdivisions. A battle is influenced at the field army level by transferring divisions and reinforcements from one corps to another to increase the pressure on the enemy at a critical point. NATO armies are commanded by ageneral orlieutenant general.
