In engineering terminology, a "black box" is a device with one or more inputs (cake ingredients, an excerpt of text in Mandarin, iron ore), one or more outputs (cake, the same text translated into Frisian, a battle golem), and internal processes that are either:
irrelevant.
unknown and/or unknowable.
Such technology falls into the hands of some organization, usually the military or a commercial [...] [tvtropes.org]