Black box

System where only the inputs and outputs can be viewed, and not its implementation

In science, computing, and engineering, a black box is a system which can be viewed in terms of its inputs and outputs, without any knowledge of its internal workings. Its implementation is "opaque" (black). The term can be used to refer to many inner workings, such as those of a transistor, an engine, an algorithm, the human brain, or an institution or government.

This keyword could refer to multiple things. Here are some suggestions: