( black boxes)
1.
A black box is an electronic device in an aircraft which records information about its flights. Black boxes are often used to provide evidence about accidents.
N-COUNT
2.
You can refer to a system or device as a black box when you know that it produces a particular result but you have no understanding of how it works.
They were part of the black box associated with high-flyer management development.
N-COUNT : usu sing