Army/ˈɑːrmi/ Definition 1 of 5Pro Tip 1/3Military Usage Mainly refers to a nation's military force on land. He served in the army for several years. Pro Tip 2/3Formal Context Used in a formal context for military discussions or news. The army has been deployed to the conflict zone. Pro Tip 3/3Collocation Importance Familiarize with common army collocations for better application. She visited the army base for an interview.