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.
An object whose name is unknown or cannot be recalled.
A bruise-like mark made during petting by pressing the mouth to the skin on one’s partner’s body and sucking.
A serif or other ornamentation on type.
A tool for making smooth, semicircular bends in conduit and pipe.
A printing defect caused by foreign matter on the printing surface resulting in a ring where the ink is missing, appearing as a spot of ink surrounded by a halo, or as an unprinted spot within a solid printed area.
Local swelling in a tissue area, especially skin, often due to injury.
An unintended negative outcome or loss in regards to a deal or action.