hēi​xiāng

black box

黑箱 hēi​xiāng
black box noun
a system or process viewed in terms of its inputs and outputs without knowledge of its internal workings, as in computing or science

They are like black boxes whose inner workings are mysterious.

flight recorder
the flight data recorder or cockpit voice recorder on an aircraft

Frequency

Written text
0.428 per million

Cross-References

Classifier

Sources

Frequency data
BCC Corpus (BLCU)