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

Noun

Two antipsychotic drugs are approved to treat irritability associated with ASD, but both come with a black box warning about safety, and neither addresses the underlying medical issues presented with autism, according to Ackerman. —Amanda Musa, CNN Money, 24 Sep. 2025

True, this would turn programs into inscrutable black boxes, but they could still be divided into modular testable units for sanity and quality checks. —Stephen Cass, IEEE Spectrum, 23 Sep. 2025

Adjective

The black box warning must be displayed for 10 seconds, unless the user clicks an X icon, and cover at least 25% of the screen of the site. —Ted Johnson, Deadline, 13 Oct. 2025

Over the summer, the district completed AA projects including the modernization of the black box theater at CCA, new locker rooms at Diegueno, and a major refresh of Crest Hall at Oak Crest, with new floor and wall finishes for the multi-use space with a stage for student performances. —Karen Billing, San Diego Union-Tribune, 7 Oct. 2025

Word History

First Known Use

Noun

circa 1945, in the meaning defined at sense 1

Adjective

1968, in the meaning defined above

Rhymes for black box

• botox
• checkbox
• comox
• cornstalks
• cowpox
• crosswalks
• deadlocks
• detox
• feedstocks
• firebox
• gearbox
• hemlocks

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