A theoretical construct or device with known input and output characteristics but unknown method of operation.
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.
A device used in phreaking that prevents the calling party from being billed for the call placed.
A type of theater characterized by a lack of decoration or complex mechanisms.
Any similar device on motor vehicles, such as rail event recorders and ship trip recorders.
To focus on the inputs and outputs without worrying about the internal complexity.
More generally, any result of mental activity; a thought, a notion; a way of thinking.
An abstract archetype of a given thing, compared to which real-life examples are seen as imperfect approximations; pure essence, as opposed to actual examples.
A conception in the mind of something to be done; a plan for doing something, an intention.
A purposeful aim or goal; intent
A musical theme or melodic subject.
An image of an object that is formed in the mind or recalled by the memory.
A vague or fanciful notion; a feeling or hunch; an impression.