From Longman Dictionary of Contemporary Englishblack boxˌblack ˈbox noun [countable] informal TTATMa piece of equipment on an aircraft that records what happens on a flight and can be used to discover the cause of accidents SYN flight recorder
Examples from the Corpus
black box• They're still looking for his black box.• The briefcase-sized black box contained a keyword selection computer.• It was a small black box, rather like the Thing, mounted on little treads.• A second later there was a loud click and buzz which could only be the black box alarm being activated.• Accident investigators have found the black box flight recorder.• New investigative techniques have opened up the black box of the brain and have begun to shed light on its inner workings.From Longman Business Dictionaryblack boxˌblack ˈbox noun [countable] informal1an electronic unit that records information on an aircraft about its height, speed etc. If the plane crashes, the black box can be examined to find the causesData from the black box recovered from the destroyed helicopter has been played back satisfactorily.2a machine that works in a secret way that is not normally explained to peopleWe found out what formulas were inside the black boxes that firms used to determine when to set off computer-driven program trades. 