M-5, a computer designed to take full command of a starship, is installed on the Enterprise. To test M-5, the Enterprise is placed in an unscheduled war game simulation with Commodore Wesley leading the opposing forces. M-5 performs splendedly with Wesley reporting the results.
Wesley: "Our compliments to the M-5 unit, and regards to Captain Dunsel. Wesley out."
McCoy: "Dunsel? Who the blazes is Captain Dunsel?"
McCoy: [as Kirk is leaving the bridge] "What does it mean, Jim? Spock? What does it mean?"
Spock: "'Dunsel', Doctor, is a term used by midshipmen at Starfleet Academy. It refers to a part which serves no useful purpose."