The term 'CONGRESSIONAL 'NO'' is a reference to the voting process in the United States Congress. When a bill or resolution is brought before the House of Representatives or the Senate, members of Congress can vote either 'YEA' or 'NAY' on the measure. The term 'NAY' is typically abbreviated as 'NAY, ' which is a three-letter word. Therefore, the crossword solution for the term 'CONGRESSIONAL 'NO'' is 'NAY.'