black box

American  

noun

1. any unit that forms part of an electronic circuit and that has its function, but not its components, specified.

2. any comparatively small, usually black, box containing a secret, mysterious, or complex mechanical or electronic device.

3. Aeronautics. an electronic device, such as a flight recorder, that can be removed from an aircraft as a single package.

4. Automotive. a device in an electronic ignition system that generates electrical pulses.

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black box British  

noun

1. a self-contained unit in an electronic or computer system whose circuitry need not be known to understand its function

2. an informal name for flight recorder

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black box Cultural  

1. A crash-resistant steel container that holds instruments that record performance data in airplanes. The data are used to analyze the causes of accidents.

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Etymology

Origin of black box

First recorded in 1940–45

Example Sentences

As well as the black box, Motability has introduced recommendations that drivers take a break every hour and aim not to do more than six journeys a day.

From BBC • Apr. 1, 2026

But her probe would be a black box that she could slow-walk indefinitely.

From Slate • Mar. 6, 2026

A 49-seat black box theater has attracted the likes of Kaia Gerber and Addison Rae’s team.

From Los Angeles Times • Mar. 2, 2026

The DIP lenders’ lawyer, Scott Greenberg, a partner at Gibson Dunn & Crutcher, said in a November hearing that his clients were lending “into a black box which seems to not have a bottom.”

From The Wall Street Journal • Jan. 22, 2026

It was a black box with a point on it that turned in a circle.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel