Dunsel

Dunsel is a slang term used by 23rd-century midshipmen at Starfleet Academy. It is used to describe a part which serves no useful purpose.

The term was used as an insult (albeit a playful one) to Captain James T. Kirk during the war games test of the M-5 Multitronic Unit created by Dr. Richard Daystrom. Commodore Robert Wesley awarded victory to the USS Enterprise, specifically with: "Congratulations to Captain Dunsel."

The word carries approximately the same meaning and emotional impact as the American English term, "Edsel." In the context of the episode, however, Kirk was stung more deeply than would be usual.