Definition of armies:
(n) :
A large, highly organized military force, concerned mainly with ground (rather than air or naval) operations.
(n) :
Used absolutely for that entire branch of the armed forces.
(n) :
The military as a whole.
(n) :
(often capitalized) Within a vast military, a very large tactical contingent (e.g. a number of divisions).
(n) :
The governmental agency in charge of a state's army.
(n) :
(figuratively) A large group of people working toward the same purpose.