I. noun
: any of several Australian eucalypts with dark foliage (as Eucalyptus bicolor, E. baueriana, E. boormani )
II. noun
1. : a usually complicated electronic device that functions and is packaged as a unit and whose internal mechanism is usually hidden from or mysterious to the user ; broadly : anything that has mysterious or unknown internal functions or mechanisms
the secrecy of Soviet society makes it a black box to Western observers — James Fallows
the cancer cell is no longer an impenetrable black box — R.A.Weinberg
2. : a crashworthy device in aircraft for recording cockpit conversations and flight data ; also : a similar device in another type of vehicle (as an automobile or ship) especially for recording vehicle performance data