# black box

> English word · Noun

## Definitions
1. A flight recorder; the brightly colored cockpit voice recorders and flight data recorders in an aircraft designed to aid in determining the cause of an accident.
2. Any similar device on motor vehicles, such as rail event recorders and ship trip recorders.
3. A theoretical construct or device with known input and output characteristics but unknown method of operation.
4. A device used in phreaking that prevents the calling party from being billed for the call placed.
5. A type of theater characterized by a lack of decoration or complex mechanisms.
6. Synonym of football (“the leather briefcase containing classified nuclear war plans which is always near the US President”)

## Etymology
* Since c. 1945 in both main senses (that is, event recorders and objects with unknown innards), which are historically related to each other; for details, see black box § History and flight recorder § Terminology.
* (a type of theater): Such theaters are often painted black.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/black-box