black box vs thingamajig

black box

noun
  • A type of theater characterized by a lack of decoration or complex mechanisms. 

  • 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 theoretical construct or device with known input and output characteristics but unknown method of operation. 

  • Any similar device on motor vehicles, such as rail event recorders and ship trip recorders. 

verb
  • To focus on the inputs and outputs without worrying about the internal complexity. 

thingamajig

noun
  • Something that one does not know the name of. 

How often have the words black box and thingamajig occurred in a corpus of books? (source: Google Ngram Viewer )