It depends on house rules, but generally the rule is you require two armies to attack anything.
armies
The plural form for the noun army is armies. The plural possessive form is armies'.
Army.
armies
No, they are two separate armies.
Countries have strong armies mostly to discourage others from attacking them.
They lacked the determination of the NVA. It is possible that maybe "attacking armies" might be inherently imbued with more determination than defending armies.
If there are not trained probably it makes it easier for the other army that is attacking to defeat them easily
A collective noun for a group of armies would be specific to that group, such as an alliance of armies, an encounter of armies, an encampment of armies, etc.The word army is a standard collective noun for:an army of soldiersan army of antsan army of caterpillarsan army of frogsan army of herrings
During World War I, the Germans had an army attacking from the south of Paris and an army attacking from the North of Paris. They intended to crush the French army caught in between. The English General was totally incompetent and got totally lost. He led his army right between the two German armies. The military maneuver is called a defeat in detail. If you can't be good, be lucky.
The plural of army is armies. As in "the two armies marched against each other".
The two armies are Alexander's army and Rome army.
armies
Armies
There were several dominant Roman armies in history. These Roman armies include the Romany Army of the Mid-Repubic, Imperial Roman Army, Middle Byzantine Army, and Komnenian Byzantine Army.
The plural form for the noun army is armies. The plural possessive form is armies'.
The plural for for the noun army is armies. Example: The armies fought bravely.