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
: 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
Theresa Gaffney, STAT, 23 Jan. 2026
The company’s seasons are likely to have two main shows a year with one in the fall at the Austin Arts Center’s main Goodwin Theater and one in the spring in the center’s smaller Garmany Hall black box space.
—Christopher Arnott, Hartford Courant, 21 Jan. 2026
Annalisa Merelli, STAT, 12 Jan. 2026
Charcoal gray, or even black, gives a small space a black box look, where there's no end in sight.
—Heather Bien, Southern Living, 7 Jan. 2026
See All Example Sentences for black box
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Noun
The Trump administration has been eagerly encouraging more (cisgender) people to use hormones, and in November, the FDA removed the black box label warning from menopause hormone products.
—Theresa Gaffney, STAT, 23 Jan. 2026
The company’s seasons are likely to have two main shows a year with one in the fall at the Austin Arts Center’s main Goodwin Theater and one in the spring in the center’s smaller Garmany Hall black box space.
—Christopher Arnott, Hartford Courant, 21 Jan. 2026
Adjective
Late last year, the Food and Drug Administration convened an expert panel to discuss easing access to testosterone replacement therapy, including the prospect of removing the hormone from the list of scheduled, or restricted, substances and taking the black box warning off testosterone products.
—Annalisa Merelli, STAT, 12 Jan. 2026
Charcoal gray, or even black, gives a small space a black box look, where there's no end in sight.
—Heather Bien, Southern Living, 7 Jan. 2026
See All Example Sentences for black box
Cite this Entry
“Black box.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/black%20box. Accessed 3 Feb. 2026.
Copy CitationMedical 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
Johnathan D. Rockoff, The Fort Worth (Texas) Star-TelegramLove words? Need even more definitions?
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