Longman Dictionary of Contemporary English - army

~ n 1 the army the part of a country's military force that is trained to fight on land in a war  (He joined the army when he was 17.) also + plural verb BrE The army are helping to clear up after the floods. | be in the army  (Both my sons are in the army.) 2 a large organized group of people trained to fight on land in a war  (The rebel armies have taken control of the radio station. | raise an army (=collect and organize an army to fight a battle)) 3 a large number of people or animals involved in the same activity  (The village hall is maintained by an army of volunteers.)  (- compare air force, navy)