The term 'DEFUNCT FORD DIV.' refers to the defunct Ford Division of the Ford Motor Company. The Ford Division was the original division of the company, established in 1903 by Henry Ford. It was responsible for the production of cars and trucks until it was discontinued in 2002. The four-letter answer to this crossword puzzle is MERC, which stands for Mercury, a brand of automobiles produced by the Ford Motor Company from 1938 to 2011.