陆军 (lùjūn) is a noun meaning "army" or "ground forces." It refers to the branch of a country's military that conducts land-based operations. It is one of the main military branches, alongside 海军 (navy) and 空军 (air force).
他在陆军服役了五年。
Tā zài lùjūn fúyì le wǔ nián.
He served in the army for five years.
陆军、海军和空军是国防的三大力量。
Lùjūn, hǎijūn hé kōngjūn shì guófáng de sān dà lìliàng.
The army, navy, and air force are the three major forces of national defense.
陆军部队已经完成了此次训练任务。
Lùjūn bùduì yǐjīng wánchéng le cǐ cì xùnliàn rènwù.
The army troops have completed this training mission.