barn door
noun
1- the large door of a barn仓库大门。
1.1
- used to refer to a large and easy target大而易击中的目标：
on the shooting range he could not hit a barn door.
射击场上又大又好打的目标他居然一个也射不中。
1.2
- a hinged metal flap fitted to a spotlight to control the direction and intensity of its beam（控制聚光灯方向和强度的）挡光板。