1. 陆军;陆军部队
    An army is a large organized group of people who are armed and trained to fight on land in a war. Most armies are organized and controlled by governments.

    e.g. After returning from France, he joined the army...
           从法国回来之后，他参了军。
    e.g. The army is about to launch a major offensive.
           陆军部队即将发动一次大规模进攻。

2. 大批;大群
    An army of people, animals, or things is a large number of them, especially when they are regarded as a force of some kind.

    e.g. ...data collected by an army of volunteers.
           由大批志愿者收集的资料
    e.g. ...armies of shoppers looking for bargains.
           成群的寻找便宜货的购物者