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

"It's like looking at a black box," LaSala added.

From Science Daily • Jun. 2, 2026

“It’s a black box to us,” says Foundation of Hearts chairman Gerry Mallon.

From The Wall Street Journal • May 15, 2026

Affectionately known as Kosmo, it's a towering black box that resembles a cross between a telephone exchange and the flight deck of an airliner.

From BBC • Mar. 6, 2026

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

From Slate • Mar. 6, 2026

Mrs. Baxter held a small black box tied with a thin pink ribbon.

From "The Red Umbrella" by Christina Gonzalez