black box

1 of 2

noun

1
: a usually complicated electronic device whose internal mechanism is usually hidden from or mysterious to the user
broadly : anything that has mysterious or unknown internal functions or mechanisms
2
: a crashworthy device in aircraft for recording cockpit conversations and flight data
3
: a device in an automobile that records information (such as speed, temperature, or gasoline efficiency) which can be used to monitor vehicle performance or determine a cause in the event of an accident

black box

2 of 2

adjective

: being or containing a warning of a serious or life-threatening side effect (such as stroke or muscle damage) that is highlighted by a black border on a prescription drug's label or accompanying literature

Examples of black box in a Sentence

Noun The black boxes were recovered from the crash site and provided useful information about the cause of the crash.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Noun
At each of the crash sites, the search for the cockpit voice recorders and flight data recorders – encased in orange metal, though often called black boxes – from the hijacked planes was underway. — Alexandra Skores, CNN Money, 10 Sep. 2026 Unlike traditional models that use physical properties in a location to simulate physical processes, machine-learning models are largely black boxes that train on past patterns and spit out predictions of future patterns. — Scott K. Johnson, ArsTechnica, 8 Sep. 2026
Adjective
The sense that a resume goes straight into a black box isn’t imagined – applications per job have more than doubled since 2022, and the average company now has 56% fewer recruiters to review them. — Owen Humphries, Fortune, 16 Oct. 2026 But in the case of a film about OpenAI, which remains such a black box to the public, that felt revelatory and shocking. — Julia Black, Vanity Fair, 13 Oct. 2026 See All Example Sentences for black box

Word History

First Known Use

Noun

circa 1945, in the meaning defined at sense 1

Adjective

1968, in the meaning defined above

Time Traveler
The first known use of black box was circa 1945

Rhymes for black box

See All Rhymes for black box

Browse Nearby Words

black-bottom
black box
blackboy
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Cite this Entry

“Black box.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/black%20box. Accessed 20 Oct. 2026.

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Medical Definition

black box

adjective
: being or containing a warning of a serious or life-threatening side effect (as stroke, muscle damage, or suicidal tendencies) that is highlighted by a black border on a prescription drug's label or accompanying literature
A "black box" warning is the most serious warning placed in the labeling of a prescription medication.—Johnathan D. Rockoff, The Fort Worth (Texas) Star-Telegram

More from Merriam-Webster on black box

Britannica.com: Encyclopedia article about black box

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