N-UNCOUNT [oft NOUN n](派士兵或飞机)侦察;(用卫星)搜索,勘测Reconnaissance is the activity of obtaining military information about a place by sending soldiers or planes there, or by the use of satellites. (派士兵或飞机)侦察;(用卫星)搜索,勘测
The helicopter was returning from a reconnaissance mission.
直升机完成侦察任务后正在返航。
The aircraft will be used for reconnaissance rather than combat.