This is the verse translation, not a definition of the individual word.
When you [O Prophet] are with them and lead them in prayer, let a group of them stand [in prayer] with you, carrying their weapons. When they have finished their prostration, let them take their positions in the rear. Then let the other group that has not yet prayed join you in prayer, keeping vigilant and carrying their arms[1]. The disbelievers wish that you would neglect your weapons and belongings, so they could launch on you a surprise attack. But there is no blame on you if you lay down your weapons because of the inconvenience of rain or because you are ill, but take all precautions. Indeed, Allah has prepared for the disbelievers a humiliating punishment.
Source
[1] This is the manner of prayer in danger on the battlefield.